Device to be implanted in human or animal tissue and method for implanting and assembling the device

ABSTRACT

An implant or endoprosthesis suitable to be implanted in human or animal tissue includes two (or more than two) parts to be joined in situ. Each one of the parts includes a joining location, the two joining locations facing each other when the device parts are positioned for being joined together, wherein one of the joining locations includes a material which is liquefiable by mechanical vibration and the other one of the joining locations includes a material which is not liquefiable by mechanical vibration and a structure (e.g. undercut cavities or protrusions) suitable for forming a positive fit connection with the liquefiable material. The joining process is effected by pressing the two device parts against each other and by applying ultrasonic vibration to one of the device parts when the two parts are positioned relative to each other such that the two joining locations are in contact with each other.

The invention is in the field of medical technology and concerns adevice to be implanted in human or animal tissue, i.e. an implant orendoprosthesis. The device comprises two or more than two device partswhich are equipped for in situ assembly, i.e. to be joined during theimplantation operation and in the implantation site. The inventionfurther concerns a method for implanting and assembling the device in ahuman or animal patient, in particular implanting it in bone tissue ofthe patient.

According to the state of the art, implants or endoprostheses consist ofmetallic, ceramic or polymer materials. Some known implants orendoprotheses comprise a plurality of parts which are assembled eitherwhen being manufactured or immediately before implantation and beforebeing positioned in the implantation site (ex situ assembly). The partse.g. consist of different materials and form implant regions havingdifferent functions, as e.g. described in the publications WO2004/017857 or WO 2005/079696. The parts may also come in setscomprising a selection of part shapes or part sizes, wherein parts arechosen and assembled immediately before implantation (ex situ) to fitthe individual implantation site (described e.g. in U.S. Pat. No.5,593,425, Bonutti). Furthermore, it is known to fix a further part tothe proximal end of an implanted implant or endoprosthesis (in situassembly) which further part then protrudes from the tissue in which theimplant or endoposthesis is implanted (e.g. crown mounted on a dentalimplant or ball mounted on the shaft of a hip joint prosthesis). It isfurther known to secure implants or endoprostheses which are implantedin the tissue by further implants (e.g. cross pins for securing theshaft of an endoprosthesis shaft). The known in situ assemblies areusually based on a bore in one of the parts and a corresponding bolt,cone or screw on the other part. Due to the named assembly means thefreedom which these assemblies can offer regarding selectable relativepositions for the assembled parts and therefore their applications arevery limited. In the above mentioned publication U.S. Pat. No. 5,593,425it is suggested to assemble endoprosthesis parts, of which one comprisesa thermoplastic material, by heating this thermoplastic material andtherewith make its surface tacky and to bring the heated and therewithtacky surface in contact with a non-thermoplastic surface of an otherendoprosthesis part in order to adhere it there. This method allows morefreedom of relative placement of the endoprosthesis parts relative toeach other, but the strength of the resulting connection is limited.

It is the object of the invention to create a device to be implanted ina human or animal patient, the device being an implant or endoprosthesisand comprising at least two parts to be assembled in situ. It is afurther object of the invention to create a method for implanting andassembling the device. The device and the method according to theinvention are to be more universally applicable than known multi-partimplants or prostheses for in situ assembly and are to allow moreflexibility regarding the relative position of the assembled partsrelative to each other, but still resulting in a strong connectionbetween the implant or prosthesis parts.

This object is achieve by the device and the method according to theinvention.

The device according to the invention comprises two (or more than two)parts which parts are equipped for being assembled, i.e. joinedtogether, using mechanical oscillation, in particular ultrasonicvibration, which is applied to one of the parts by contacting this partwith a mechanically vibrating tool. The device parts usually consist ofan artificial material but some of the parts may also consist of bonetissue. Each one of the two parts of the device comprises a joininglocation, the two joining locations being matched to each other forbeing in contact with each other when the parts are positioned to bejoined and for being connected to each other after the joining process,wherein the resulting joint is a positive fit connection.

For achieving a positive fit connection, a first one of each matchedpair of joining locations comprises a material having thermoplasticproperties and being liquefiable by mechanical vibration, which materialforms the surface of the joining location or can be pressed to thissurface from the inside of the part by application of the mechanicalvibration. A second one of each pair of matched joining locationscomprises a material which is not liquefiable by the mechanicalvibration to be used for joining the two device parts (e.g. metal,ceramic material or polymer with duroplastic properties or withthermoplastic properties but with a melting temperature which isrelevantly higher than the melting temperature of the liquefiablematerial) and it further comprises a structure being suitable for apositive fit connection with the material of the first joining locationwhen this material is liquefied, made to penetrate into the structureand to re-solidify within this structure. The structure of the secondjoining location comprises an undercut cavity or protrusion or aplurality of undercut cavities or protrusions, wherein one or arelatively small number of cavities (e.g. bores or grooves) orprotrusions having a defined form and a size of preferably a few mm isprovided and/or a large number of cavities and protrusions having randomforms, i.e. being formed by e.g. an open-porous surface material or asurface coating consisting of assembled particles (e.g. sinteredmaterial). For enabling penetration of the surface structures by theliquefied material of the first joining location and for realizing astable joint, the cavities of the porous or particulate surface materialneed to have a size of at least about 0.3 mm and the surface structureneeds to have a depth which is at least twice as large as the finenessof the structure (pore size of the porous material, particle size of theparticulate coating).

At least one of the device parts to be joined together further comprisesa contact location in which it is able to be contacted with a vibratingtool (e.g. sonotrode of an ultrasonic device) for the joining process.The part comprising the contact location may comprise the first or thesecond joining location.

At least the device part comprising the contact location and preferablyboth device parts are designed as mechanically stable oscillators suchthat mechanical vibration applied to the contact location is transmittedby the oscillator to the joining location with as little damping loss aspossible and in particular without reduction of the mechanical stabilityof the oscillator during the application such that it becomes possibleto liquefy enough (but not more) material in the region of the joininglocations for achieving the desired positive fit connection but withoutfurther changing form or material of the device part. For achieving goodoscillator properties the device parts are made of materials having anelasticity module of at least about 0.5 GPa for low damping losses. Thesurface of either joining location is preferably equipped withprotruding energy directors (protruding pyramids, cones, combs etc.having a height of at least 10 μm) which, on application of thevibration, locally concentrate the vibrational energy such causing highlocal shearing stresses and therefore local and fast liquefaction of thesurface material even if the melting point of this material is as highas 200 to 450° C. By such local liquefaction, the amount of materialwhich is liquefied can be kept small (e.g. just enough for penetratingthe structure of the second joining location) and therefore the thermalloading of the tissue remains within physiologic limits (allowing forfunctional regeneration of the tissue) even when macroscopic cavities ofthe second joining location need to be filled with the liquefiedmaterial.

Depending on the form of the two joining locations, the liquefiedmaterial may allow adjustments of the relative position of the twodevice parts during the joining process, which makes it possible to insitu adapt the relative position of the two device parts to the implantsite. Larger such in situ adaptation is made possible, if at least oneof the joining locations is designed such that it allows joining of thetwo parts in a selected one of a plurality of different possiblerelative positions.

According to some aspects of the invention, at least one part of thedevice or both parts of the device are positioned and possibly fixed inthe tissue, the two parts are positioned relative to each other suchthat their joining locations are in contact with each other and then themechanical vibration is applied to either one of the parts for joiningthe two parts by liquefying the liquefiable material of the firstjoining location, by making it to penetrate into the cavity or cavitiesor between and under the protrusion or protrusions of the second joininglocation and letting it re-solidify there. The mechanical vibration usedfor joining the device parts has e.g. a frequency of 2 to 200 kHz and ispreferably ultrasonic vibration.

For fixing the device parts to the tissue per se known methods, such ase.g. screwing, clamping, pinning, cementing, suturing or press-fittingare applicable. According to preferred embodiments of the methodaccording to the invention the application of mechanical vibration isused not only for joining the two device parts together but also forfixing one or both of the device parts in the tissue by anchoring it inthe tissue (in particular in bone tissue) with the aid of a liquefiablematerial. The two applications of mechanical vibration may be carriedout simultaneously and using the same contact location and the samevibrating tool and/or in succession and using different contactlocations and the same tool or different tools.

Devices to be anchored in tissue, in particular in bone tissue, with theaid of a liquefiable material and mechanical vibration and methods forimplanting such devices are described in the publications WO2002/069817, WO 2004/017857 or WO 2005/079696, the disclosure of thesepublications being enclosed herein by reference.

Experiments show that successful anchorage effected simultaneously withthe joining is easily effected for the device part to which thevibration is applied, and anchorage effected before the joining iseasier conserved when the subsequent vibration for the joining processis not applied to the anchored device part. These findings are due tothe fact that transmission of the vibration through the joininglocations being in contact with each other is hardly possible as theliquefiable material being present where the two joining locations arein contact is liquefied substantially immediately on application of thevibration such that hardly any vibrational energy can be transmittedthrough the joining locations. This means that beyond the joininglocations hardly any liquefaction by mechanical vibration occurs andtherefore neither anchorage in tissue with the aid of liquefiablematerial and mechanical vibration nor damaging such anchorage can beeffected.

In the present text the term “liquefiable material” is used for amaterial comprised by the device which material can be liquefied bymechanical vibration, e.g. by ultrasonic vibration. If the liquefiablematerial is to take over load-bearing functions and/or if only a verylimited amount thereof at predetermined locations is to be liquefied,the liquefiable material is a material in which the mechanical vibrationcauses no internal stress strong enough for plastifying or liquefyingthe material but on whose surface such liquefaction can be effected bycontact with a non-vibrating element, wherein such contact is limited topoints or lines (energy directors). Such materials are materials havingthermoplastic properties and an elasticity module of at least 0.5 GPa.If the liquefiable material is not to have a load-bearing functionand/or if more of the material is to be liquefied by the mechanicalvibration, the liquefiable material may be a material as above describedbut may also be a material with thermoplastic properties and with asmaller elasticity module.

In the present text the term “non-liquefiable material” is used for anadditional material comprised by the device. In the non-liquefiablematerial mechanical vibration, e.g. ultrasonic vibration, as used forliquefaction of the liquefiable material, causes no internal stresswhich is strong enough for liquefying the material nor is such vibrationable to liquefy the non-liquefiable material in surface areas being incontact with a non-vibrating element even if such contact is limited tosingle points or lines (energy directors).

From the above follows that the properties of the non-liquefiablematerial of a specific device depend on the properties of theliquefiable material of the same device. Generally speaking: the lessvibrational energy is used for liquefaction of enough of the liquefiablematerial, the easier liquefiable the non-liquefiable material may be.Therefore a thermoplastic material with a high melting temperature (e.g.PEEK) is suitable to be used as non-liquefiable material if theliquefiable material is e.g. PLLA. On the other hand the samethermoplastiv material (e.g. PEEK) is suitable as liquefiable materialif the non-liquefiable material is e.g. titanium or a ceramic material.

In the present text the term “mechanically stable oscillator” is usedfor a body which is able to be vibrated by e.g. ultrasonic vibrationwithout being internally affected by the vibration. A mechanicallystable oscillator comprises no form element which is deformed by thevibration, it comprises no material with a high damping loss (e.g.elasticity module considerably less than 0.5 GPa) and, if it comprisesmore than one part, the parts are joined such that vibration passesthrough the joint substantially without loss or reflection.

In the present text the terms “bone tissue” or “bone” are used toencompass not only viable bone tissue but also bone replacementmaterial.

The invention comprises aspects A to E as detailed below.

-   -   Aspect A: The first device part forms a base in bone tissue for        the second device part. The base part is equipped for being        anchored in bone tissue with the aid of a liquefiable material        and mechanical vibration and preferably comprises the first        joining location. A distal end of the second device part (based        part), is to be fixed to the bone tissue via the base part and        preferably comprises the second joining location. The base part        is anchored in the bone tissue by mechanical vibration and the        based part is joined to the base part again by mechanical        vibration. Depending on the specific design of base part and        based part, anchorage of the base part in the bone tissue and        joining of the based part thereto are carried out in two        successive steps, wherein the vibration is first applied to the        base part and then to the based part, or in one step, wherein        the vibration is applied to the base part.    -   Aspect B: The first device part is again a base part equipped        for being anchored in bone tissue with the aid of a liquefiable        material and mechanical vibration. The base part is pin-, plate-        or possibly wedge-shaped and preferably comprises the first        joining location, the based part (second device part) preferably        comprising the second joining location. For fixing the device to        bone tissue, the based part is positioned relative to the bone        tissue, its joining location facing the bone tissue. The base        element is then pushed between the bone tissue and the based        part and simultaneously mechanical vibration is applied to its        proximal end, such that on one of its lateral sides the base        part is anchored in the bone tissue and on an opposite lateral        side it is joined to the based part, thereby fixing the based        part relative to the bone tissue. A similar method can be used        for fixing instead of a device part (based part) to bone tissue,        a device part to another device part or a bone tissue part to        another bone tissue part (e.g. bone fragments).    -   Aspect C: The first device part is again a preferably pin- or        plate-shaped base part equipped for being anchored in bone        tissue with the aid of a liquefiable material and mechanical        vibration and preferably comprising the first joining location,        the second device part (based part) preferably comprising the        second joining location. A tunnel is provided in the bone        tissue, the second device part is positioned adjoining a distal        tunnel mouth and the base part is brought through the proximal        tunnel mouth into the tunnel and at the distal tunnel mouth in        contact with the joining location of the based part. Base part        and based part are then joined together in the region of the        distal tunnel mouth by applying mechanical vibration to the base        part near the proximal tunnel mouth, wherein simultaneously with        the joining of the two device parts, the base part is anchored        in the bone tissue of the tunnel walls. The base part may be        fixed to the bone tissue by other means than anchorage with the        aid of a liquefiable material and mechanical vibration. Instead        of in bone tissue, the tunnel may also be provided in a further        device part.    -   Aspect D: a plurality of device parts is pre-assembled such that        the device parts are movable relative to each other in a limited        way. Selected ones of the device parts may be equipped for being        anchored in bone tissue with the aid of a liquefiable material        and mechanical vibration. The device parts are brought to the        implantation site in a pre-assembled configuration or are        pre-assembled in the implantation site. In the pre-assembly        specific ones of the device parts are still moveable relative to        each other in a limited manner. The pre-assembled device parts        are positioned relative to each other in a site-specific        arrangement by moving the specific device parts relative to each        other. The device parts are then locked in this site-specific        configuration by being joined to each other with the aid of        mechanical vibration, for which joining, adjacent and relative        to each other moveable device parts are equipped with matched        joining locations which face each other. Anchorage of the        correspondingly equipped device parts takes place simultaneously        with the joining or in a preliminary step. There may not be any        anchorage of device parts in the bone tissue.    -   Aspect E: a plurality of device parts is brought to the        implantation site in succession either along substantially the        same path or along different paths and the device parts are        joined to each other in the implantation site, joining being        effected using mechanical vibration being applied to at least        one of the device parts. Selected ones of the device parts may        be equipped for being anchored in bone tissue with the aid of a        liquefiable material and mechanical vibration. The device parts,        which are equipped with matched pairs of first an second joining        locations where they are to be joined, are positioned relative        to each other in the implantation site with matched joining        locations facing each other and are then joined to each other        with the aid of mechanical vibration. Anchorage of the        correspondingly equipped device parts takes place simultaneously        with the joining or in a preliminary step. There may not be any        anchorage of device parts in the bone tissue.

Suitable liquefiable materials for joining the parts of the deviceaccording to the invention are not biologically resorbable, whereasliquefiable materials for anchoring a part of the device in bone tissuemay either be resorbable or non-resorbable.

Suitable non-resorbable liquefiable materials for first joininglocations and possibly also for the anchorage of a device part are e.g.:polyolefines (e.g. polyethylene), polyacrylates, polymethacrylates,polycarbonates, polyamides, polyesters, polyurethanes, polysulfones,liquid-crystal-polymers (LCPs), polyacetals, halogenated polymers, inparticular halogenated polyolefines, polyphenylene sulphones,polysulfones, Polyaryletherketones (E.g. polyetheretherketone PEEK,available under the trade name Victrex 450G or Peek Optima from Invibo)polyethers, or corresponding copolymers and mixed polymers or compositescontaining said polymers and fillers or reinforcing agents such as e.g.fibers, whiskers, nanoplatelets, or nanotubes. Particularly suitable arepolyamide 11 or polyamide 12.

Suitable resorbable liquefiable materials for anchorage of a device partin bone tissue are e.g.: thermoplastic polymers based on lactic and/orgluconic acid (PLA, PLLA, PGA, PLGA etc) or polyhydroxy alkanoates(PHA), polycaprolactones (PCL), polysaccharides, polydioxanones (PD),polyanhydrides, polypeptides, trimethyl-carbonates (TMC), orcorresponding copolymers, or mixed polymers, or composites containingsaid polymers. Particularly suitable as resorbable liquefiable materialsare: poly-LDL-lactide (e.g. available from Bohringer under the tradename Resomer LR708) or poly-DL-lactide (e.g. available from Bohringerunder the trade name Resomer R208), as well as corresponding copolymersand mixed polymers or composites containing said polymers and fillers orreinforcing agents such as e.g. fibers, whiskers, nanoplatelets, ornanotubes.

The device according to the invention serves the same purposes as knownimplants and endoprostheses. The device serves in particular for fixingone viable tissue part to another viable tissue part, wherein the deviceaccording to the invention constitutes a fixing element, in particular aload bearing fixing element between the two tissue parts. The device mayalso serve for fixing an artificial element replacing a natural tissuepart or an auxiliary element (e.g. auxiliary support part), wherein thedevice according to the invention constitutes the replacement part orauxiliary part as well as the fixing means.

The advantage of the device and the method according to the invention isthe ease of the in situ assembly, the robustness of the assembly, thecharacter of the assembly which makes it non-reversible underphysiologic conditions and the easy and little limited in situadaptability of the assembly.

For carrying out the method according to the invention a vibrationdevice is used, e.g. an ultrasonic device comprising an ultrasonictransducer, a booster and a sonotrode or a sonotrode (vibrating tool)and an acoustic coupling piece (vibrating tool), wherein the sonotrodeor the coupling piece is advantageously exchangeable. Preferably a setis provided which set comprises, in addition to device parts, vibratingtools with distal ends adapted to the contact locations of the deviceparts and proximal ends adapted to a fixation point of the vibrationdevice or sonotrode respectively. The sets may further comprise printedor otherwise recorded instructions regarding implantation parameterssuch as e.g. vibration frequencies and application times suitable forthe joining and possibly anchoring processes for implantation andassembly of the device parts of the set.

Exemplary embodiments of the method and the device according to theinvention are described in further detail in connection with thefollowing Figures, wherein:

FIGS. 1 to 7 illustrate structures of second joining locations andjoints achieved by joining matched pairs of joining locations;

FIGS. 8 to 14 show a first group of exemplary embodiments of aspect A ofthe invention, wherein a distal end of the based part is fixed withinbone tissue via a base part, wherein the base part is anchored within anopening provided in the bone tissue, wherein the based part is fixed inor on the base part, and wherein the based part has varying functions;

FIGS. 15 and 16 show a second group of exemplary embodiments of aspect Aof the invention, wherein this group is similar to the first group butwherein the base part is anchored in the marrow space of a suitablyprepared tubular bone;

FIGS. 17 to 20 show a third group of exemplary embodiments of aspect Aof the invention, for which the based part is joined to the proximalbase part end which protrudes from an opening which is provided in thebone tissue and in which the base part is anchored;

FIGS. 21 to 24 show a first group of exemplary embodiments of aspect Bof the invention, wherein a based part is positioned in an opening inbone tissue with the aid of one or a plurality of base parts beingpushed into the opening beside the based part;

FIGS. 25 to 32 illustrates a second group of embodiments of aspect B ofthe invention, wherein a based part is fixed relative to a bone surfacewith the aid of one or a plurality of base parts;

FIGS. 33 to 35 show a third group of embodiments of aspect B of theinvention, wherein the based part to be fixed relative to bone tissue isa bone tissue part;

FIGS. 36 and 37 show a fourth group of embodiments of aspect B of theinvention, wherein the base part serves to fix a based part relative toa further device part;

FIGS. 38 to 46 show a first group of embodiments of aspect C of theinvention, wherein a based part is fixed relative to a bone surface by abase part which is introduced through the bone tissue beneath the bonesurface to be joined to the based part and to be simultaneously anchoredin the bone tissue with the aid of a liquefiable material and mechanicalvibration;

FIGS. 47 and 48 illustrate a second group of embodiments of aspect C ofthe invention wherein the base part is introduced through a furtherimplant part to be joined to the based part;

FIGS. 49 to 54 show a first group of embodiments of aspect D of theinvention, wherein a pre-assembled plurality of device parts is arrangedin a site-specific configuration and the device parts are then joined toeach other;

FIGS. 55 to 61 show a second group of embodiments of aspect D of theinvention, wherein the device comprises, in addition to the plurality ofpre-assembled or pre-assemblable device parts, a locking part forlocking the pre-assembled device parts in the site-specificconfiguration;

FIGS. 62 to 64 show exemplary embodiments of aspect E of the invention,wherein a plurality of device parts is assembled and joined in situ.

FIGS. 1 to 7 illustrate exemplary embodiments of matched pairs of firstand second joining locations suitable for the devices according to theinvention and connections between such joining locations. The firstjoining location F comprises a liquefiable material and possibly energydirectors E, the second joining location S comprises an undercutstructure of a non-liquefiable material and possibly energy directors E.For joining the two matched joining locations, these are pressed againsteach other and mechanical vibration is coupled into one of the partscomprising either the first or second joining location from a sideopposite the joining location. Pressure and vibration cause theliquefiable material in the region of the energy directors to liquefyand to penetrate in a liquid state into the structure of the secondjoining location and, on re-solidification, to form therewith a positivefit connection.

The main feature of joining two device parts comprising a matched pairof first and second joining locations using mechanical vibration is thefact that the liquefiable material of the first joining location isliquefied and penetrates in a liquid state into the structure of thesecond joining location which is usually undercut in the direction ofthe liquid flow. The resulting positive fit structures of theliquefiable material are characterized by forms which are dependent onthe surface tension of the liquid state. The liquefiable material ofthese structures may adhere to the material of the second joininglocation but there is no necessity that it does.

FIGS. 1 to 3 show as a first example of a second joining location S afoam structure e.g. consisting of a metal, e.g. titanium. FIG. 1 showsthe foam structure before being penetrated by the liquefiable material,FIG. 3 shows a pin of the liquefiable material being anchored in thefoam structure and FIG. 2 shows in a larger scale the interpenetrationof the foam structure by the liquefiable material afterre-solidification, i.e. the positive fit connection between the two.This positive fit connection which is visible in FIGS. 2 and 3 comprisesin this first example structure elements of a size in the region ofabout 1 mm or less. A first joining location matched to the joininglocation as shown in FIGS. 1 to 3 comprises a liquefiable material, isadapted to the outer surface of the foam material (e.g. even) and islarge enough to cover a plurality of the structure elements. Thestructure elements of the foam structure are able to act as a pluralityof energy directors such that the first joining location does not needto be equipped with energy directors. However, the first joininglocation may also be constituted by a more or less pointed distal end ofa pin-shaped device part, which pointed end acts as energy director.

FIG. 4 shows in a cascade of three scales a second example of the secondjoining location and a positive fit connection between this secondjoining location and a first joining location. The illustrated secondjoining location is constituted by the surface of a hip joint prosthesisby S+G Implants GmbH, Lübeck, Germany. The surface structure of suchimplants consists of a metal (preferably titanium or a titanium alloy)and is e.g. produced by sintering a particulate material or by lost formmolding. The structure elements have an average size from about 1 mm toabout 2 mm. A first joining location matched to the second joininglocation according to FIG. 4 comprises a liquefiable material and isadapted to cover a plurality of the structure elements as discussed forthe joining elements according to FIGS. 1 to 3. If the structureelements of the second joining location are more rounded than edgy, itis advantageous to equip the matched first joining location with energydirectors.

Similar structures as shown in FIG. 4 being suitable for second joininglocations may be made of trabecular metal by Zimmer, or of wire mesh asknown from implants by Johnson & Johnson. Implants by Eska also havesuitable surfaces.

FIG. 5 illustrates second joining locations S comprising a more or lessregular pattern of undercut openings (e.g. bores or grooves), which aremanufactured or molded. In the second joining location S on the left,the mouths of the undercut openings protrude slightly from the overallsurface and therewith are capable of acting as energy directors. Amatched first joining location F may be completely even. The structureof the second joining location S on the left of FIG. 5 does not compriseenergy directors and therefore energy directors E are advantageouslyprovided on the first joining location. The second joining locationstructures according to FIG. 5 advantageously have a size of about 1 toseveral mm and the first joining location covers a plurality thereof.

FIG. 6 shows a matched pair of joining locations F and S similar to thejoining locations according to FIG. 5 wherein the second joininglocation structure comprises undercut protrusions (e.g. heads or combswith a narrower neck region) instead of openings. These protrusions, ifequipped with more or less sharp edges or points act as energy directorsalso.

FIG. 7 shows a last example of a matched pair of joining locations,wherein the structure of the second joining location S, which is againan undercut opening, is larger than the first joining location F. Thefirst joining location is situated at a distal end of a pin-shaped part,which pin-shaped part is introduced into the opening, when the parts tobe joined are pressed against each other. The distal end of the pin ise.g. pointed for being capable of acting as energy director and the pincomprises enough of the liquefiable material for filling the undercutopening constituting the second joining location.

FIGS. 8 to 14 illustrate a first group of embodiments of aspect A of theinvention and applications thereof. The device is an implant or anendoprosthesis and comprises a base part (first device part) and a basedpart (second device part), the based part being based in the bone tissuevia the base part by being joined to the base part. The base part isadapted to fit into an opening to be provided in bone tissue and it isequipped for being anchored in this opening with the aid of a firstliquefiable material and mechanical vibration. For this purpose itcomprises the liquefiable material at least in surface areas to be incontact with the bone tissue or the liquefiable material is providedinside the base part and for the anchorage is pressed through openingsto surfaces in contact with the bone tissue. The base part furthercomprises preferably on its proximal side one of the joining locations,preferably the first joining location. The based part comprises a distalend adapted to be joined to the base part and comprising one of thejoining locations, preferably the second joining location.

FIG. 8 shows an anchor for e.g. anchoring a suture 21 or wire or otherflexible device part relative to bone tissue. The anchor comprises abase part 1 (first device part) to be retained in an opening of bonetissue and a based part 2 (second device part), whose distal end isequipped for being retained in the base part 1 and whose proximal end isequipped for holding the suture or wire (further device part). The basepart 1 is equipped for being anchored in hard tissue, in particular inbone tissue, with the aid of a liquefiable material and mechanicalvibration and it comprises the first joining location 3. At least partof the outer surface of the base part 1 comprises a liquefiable materialand possibly energy directors in form of ribs or other protrusions. Theproximal surface of the base part is suitable for being contacted with avibrating tool (contact location 4 for application of mechanicalvibration for anchoring the base part in the bone tissue). The base part1 further comprises an opening 5 extending from its proximal facetowards the distal end, wherein the inner surface of the opening 5comprises a liquefiable material and possibly energy directors (firstjoining location 3). The base part 1 consists e.g. entirely of theliquefiable material, e.g. of a thermoplastic polymer.

The based part 2 comprises, at its distal end, the second joininglocation 6 (e.g. according to any of FIGS. 1 to 6) and at its proximalend the contact location 7 for the application of the mechanicalvibration for the joining process. The based part 2 is e.g. made of asuitable metallic material and its distal end is matched to the opening5 of the base part 1. The second joining location 6 comprises e.g.undercut cavities and possibly energy directors (e.g. axial ribs).

For implanting and assembling the device comprising the base part 1, thebased part 2 and possibly the suture 21 or wire, the base part 1 is e.g.positioned in a bore 10 provided in the bone tissue 11 and a vibratingtool 12 (vibrating tool for the anchoring process, e.g. sonotrode of anultrasonic device) with a distal face being adapted to the proximal face(contact location 4) of the base part 1 is pressed against this proximalface. Caused by the action of vibration and pressure, the liquefiablematerial in contact with the bone tissue is liquefied andinterpenetrates the porous structure of the bone tissue to form thedesired anchorage of the base part 1 on re-solidification. Due to thehigh elasticity module of the base part material and due to the energydirectors on its outer surface or on the bone surface, the base partmaterial is only liquefied on this outer surface, the body of the basepart keeping all its mechanical stability and strength such that thebase part is able to function as a mechanically stable oscillator duringthe whole application of the mechanical vibration.

When the base part 1 is anchored in the bone tissue 11, at least thedistal end of the based part 2 is introduced in the opening 5 of thebase part and a further vibrating tool 15 (vibrating tool for thejoining process) with a distal face being adapted to the contactlocation 7 of the based part 2 is applied to the based part. Applicationof mechanical vibration 1 liquefies the liquefiable material of thefirst joining location 3 in the opening 5 of the base part and makes itto fill the undercut cavities provided in the second joining location 6to form a positive fit connection with the first joining location 3 ofthe base part and thereby joining the based part 2 to the base part 1.

The based part 2 may have various functions which are different from thefunction illustrated in FIG. 8 (suture or wire anchor), for whichfunctions the proximal end of the based part is correspondingly adapted.Exemplary further functions of the based part 2 are fixation of soft orfurther hard tissue relative to the bone tissue, fixation of a rod, arod clamp as used in spinal fusion or external fixation, of a supportingplate as used for osteosynthesis purposes or of another auxiliary deviceas for anchoring e.g. a tracker for navigation. For such fixationpurposes the proximal end of the based part 2 may e.g. be equipped withan outer or inner thread. The base part 1 and the based part 2 togethermay also constitute a dental implant to which a further dentalprosthesis part is to be fixed.

The main advantage of the two-part device according to FIG. 8 over acorresponding one-part implant being anchored in the bone tissue withthe aid of a liquefiable material and mechanical vibration is the fact,that the based part has at least a limited adjustability when the basepart is already definitively set in the bone tissue. Liquefaction of thematerial surrounding the opening 5, allows to force the based part intoa desired position and orientation relative to the base part which maynot exactly correspond with the original opening 5. Furthermore, a roundor polygon form of the cross section of the opening 5 and the distal endof the based part 2 allows to select a desired one of a plurality ofpossible rotational positions of the based part relative to the basepart. A further advantage of the embodiment according to FIG. 8 is thefact that both device parts can be made of one material only (nomulti-material parts to be manufactured), wherein the high strengthmaterial needed for fixing a further device part is suitable also forthe second joining location.

Device and method as illustrated in FIG. 8 may be altered in variousways, resulting e.g. in the following further embodiments:

-   -   The base part comprises a core made of a non-liquefiable        material, which core carries the liquefiable material for        anchoring the base part in the bone tissue on its outer surface        and which core comprises an opening constituting the second        joining location (the core material being e.g. a sintered        material presenting in the opening 5 a porous surface to be        interpenetrated by the liquefiable material of the first joining        location, pair of matched joining locations according to e.g.        FIG. 4), and the based part comprises at least in the region of        its distal end this liquefiable material constituting the first        joining location (see also FIG. 9).    -   The base part is made of a non-liquefiable material and        comprises passages connecting the opening 5 with the outer        surface and a liquefiable material is provided in the opening 5.        For anchoring the base part in the bone tissue, mechanical        vibration and pressure are applied to the liquefiable material        in the opening 5 for pressing it partly through the passages and        into the bone tissue, the liquefiable material remaining in the        opening 5 constituting the first joining location (see FIG. 11).    -   The base part consists entirely of a non-liquefiable material        and is fixed in the bone tissue e.g. by comprising a thread and        by being screwed into the bone tissue. The base part is equipped        with the second joining location (e.g. according to FIG. 7) and        the based part is equipped with the first joining location.    -   Instead of an opening 5, the base part comprises a proximal        protrusion corresponding to an opening in the based part where        the joining locations are provided (see FIG. 14).

FIG. 9 shows a further exemplary embodiment of aspect A of theinvention. The device is suitable for being implanted and assembled withthe method as shown in FIG. 1. The base part 1 comprises a core 22 of anon-liquefiable material, which core 22 carries on its outer surface theliquefiable material for anchoring the base part 1 in the bone tissue,and it further comprises an opening 5 extending from the proximal facetowards the distal end of the base part and constituting the secondjoining location (according to FIG. 7). This opening 5 is a bore with anenlarged bottom region serving as undercut cavity for the positive fitconnection with the based part 2 but also for snapping the based part inbefore the joining process.

Two versions 2.1 and 2.2 of the based part are shown, wherein bothversions consist of the liquefiable material and comprise a distal endbeing equipped for being snapped into the enlarged bottom region of theopening 5. Version 2.1 of the based part comprises a groove 25 runningacross its distal face and possibly carrying on along the lateralsurface of the based part to its proximal face. The groove 25 is shapedto be capable of guiding a suture 21, such that when the based part 2 issnapped into the base part 1, the suture 21 can be moved along thegroove e.g. for being tightened. On joining the based part 2.1 to thebase part 1, the material around the groove 25 is liquefied and onre-solidification the based part 2 is joined to the base part and at thesame time the suture 21 is fixed in the groove 25.

Version 2.2 of the based part comprises a suture 21 being fixed to it,e.g. by being positioned in the mold in which the based part is producedby injection molding. For enabling adjustment of the position of thesuture 21 relative to the anchored base part 1, the based part 2.1 or2.2 has e.g. a round cross section and can be rotated in the opening 5when being snapped into the latter.

FIG. 10 shows a further exemplary embodiment of aspect A of theinvention. The illustrated device again serves as a suture anchor andagain comprises a base part 1 and a based part 2 and is implantedaccording to the method as shown in FIG. 8. Based part 2 and base part 1are adapted to each other such that the based part 2 can be snapped intothe opening 5 of the base part 1 in at least two different depths. Afirst end of the suture 21 is e.g. fixed in the based part 2 and asecond end of the suture 21 is threaded e.g. through soft tissue 27 andthen through bores 28 and 29 leading through base part 1 and based part2 and being aligned to each other when the based part is clicked intothe base part in its outermost clicking position. When the second sutureend is fixed in any suitable position, the suture tension can beincreased by pressing the based part 2 into a deeper snap position. Thebased part 2 together with the suture 21 is then fixed in the base partby applying the mechanical vibration to the proximal face of the basedpart 2.

FIG. 11 shows a further application of a device according to aspect A ofthe invention. The device serves e.g. for fixing soft tissue (e.g.ligament or tendon 31) relative to the bone tissue 11 in which the basedpart 2 is fixed via the base part 1.

The base part 1 comprises a perforated sleeve 1.1 comprising on itsinside surface energy directors and consisting of a non liquefiablematerial and an insert 1.2 of a liquefiable material which is positionedin the sleeve 1.1. The sleeve is positioned in an opening 10 which isprovided in the bone tissue 11 and is pressed into the sleeve andvibrated by a first vibrating tool 12 positioned against the proximalface of the insert 1.2. The insert material is thereby liquefied andpressed through the sleeve perforations into the bone tissue 11 of thewall of opening 10 such anchoring the base part 1 in the bone tissue.The rest of the insert in the sleeve constitutes the first joininglocation.

The based part 2 consists of a non-liquefiable material and comprises ahead 30 for being retained in a tendon or ligament 31 through which thedistal end of the based part 2 is pushed before it is joined to the basepart. The distal end of the based part constitutes the second joininglocation by comprising a head which is preferably pointed (energydirector). For joining the based part to the base part, a furthervibrating tool 15 or the same one (12) as for anchoring is positionedagainst the head 30.

FIG. 12 shows very schematically a further device according to aspect Aof the invention, which device is applicable for fixing e.g. a ligamentor tendon 31 to bone tissue. The device is equipped similar to thedevices as illustrated in FIG. 8, 9 or 11. Other than shown in the namedFigs. though, the base part 1 of the device according to FIG. 12 iscapable to accommodate more than one based part 2 of which only one isillustrated. The base part 1 may have any suitable form, e.g.substantially round or substantially rectangular. The based part 2 shownin FIG. 12 comprises barbs which are able to preliminarily retain thebased part 2 in the corresponding opening 5. It is advantageous to firstposition and preliminarily retain all based parts 2 in theircorresponding openings 5 in the anchored base part 1 and only then tofinally join all based parts 2 to the base part 1 with the aid of themechanical vibration being applied to the head 30 of each one of thebased parts. The barbs may also constitute the structure of the secondjoining location (second joining location according to FIG. 6).

FIG. 13 shows a device according to aspect A of the invention, in whichthe based part 2 is a suture 21 and which enables anchorage of thesubstantially pin-shaped base part 1 and joining of base part 1 andsuture 21 (based part 2) simultaneously.

The base part e.g. consists of the liquefiable material and the regionsin which it is anchored in the bone tissue are substantially the same asthe first joining locations, namely the lateral surfaces of the basepart. The suture 21 consists of a non-liquefiable material. It is woundand possibly knotted round the base part 1 for which a groove may beprovided on the base part, in particular for passing the suture from thelateral sides of the base part to the proximal face thereof (groove 32).The base part 1 and the suture (based part 2) are together introducedinto a corresponding opening provided in the bone tissue and themechanical vibration is applied to the proximal end of the base part,whereby the base part 1 is anchored in the bone tissue on its distal andlateral sides and at the same time the suture 21 is joined to the basepart 1.

FIG. 14 illustrates a further application of a two part device to beimplanted e.g. according to the method as illustrated in FIG. 8. Theapplication concerns resurfacing of a bone or cartilage surfaceconstituting a bearing surface in a joint. FIG. 14 illustratesresurfacing of a femoral head, the application may however in the samemanner concern a cup-like structure. Such resurfacing implants replaceprimarily the destroyed cartilage layer but try to spear most of theunderlying bone structure. Comparable approaches can be used for almostall joints in the human skeleton, being convex, concave, flat or of amulti-curvature geometry.

FIG. 14 also illustrates an embodiment of aspect A of the invention inwhich the base part 1 does not comprise an opening for the distal end ofthe based part 2, but in which the base part 1 comprises a protrusion 39and the based part 2 comprises an opening 41 adapted to the protrusion(also possible: opening on base part and protrusion on based part). Thisprinciple is adaptable as a variant to other embodiments of aspect A ofthe invention as described above. Furthermore, FIG. 14 illustrates abase part 1 which is not anchored in one opening provided in the bonetissue but in a plurality of such openings, which plurality of openingsmay be rather small (e.g. two as illustrated) or very large, i.e. beingconstituted by a natural or manufactured roughness of a bone surface(e.g. surface of cancellous bone). As mentioned for the feature of thebase part comprising a protrusion adapted to a based part opening, thefeature of the plurality of openings provided in the bone tissue foranchorage of the base part is adaptable to other ones of the abovedescribed embodiments of aspect A of the invention.

In the device according to FIG. 14, the base part 1 is anchored in aplurality of openings of the correspondingly prepared femoral bone. Thebase part 1 comprises a plurality of distal projections which comprisethe liquefiable material and which reach into the bone openings and areanchored therein with the aid of the liquefiable material and mechanicalvibration. The proximal side of the base part is e.g. made of a metal,ceramic, or non-liquefiable polymer material and comprises a proximalprotrusion 39 comprising a surface structure with undercut cavities(second joining location). The based part 2 comprises the bearingsurface (40) replacement and opposite the bearing surface an opening 41wherein the liquefiable material of the first joining location issituated.

FIGS. 15 and 16 illustrate a second group of exemplary embodiments ofaspect A of the invention. These embodiments differ from the abovedescribed embodiments of a first group in that the opening in the bonetissue in which the base part 1 of the device is anchored is not anopening which is made in the bone tissue but is the marrow space of atubular bone 45. The device is e.g. an endoprosthesis replacing a jointpart.

FIG. 15 illustrates a substantially hollow base part 1 made e.g. of theliquefiable material (also possible: comprising core of non-liquefiablematerial coated at least partly with the liquefiable material) anddesigned for being anchored not only on the inside bone surface of thetubular bone 45 but also on its face created by removing the one endsection of the tubular bone 45 which is to be replaced by the device.The bone section to be replaced is e.g. part of a smaller joint (e.g.finger joint). The proximal end of the based part 2 represents most ofthe replacement and the distal end is designed for fitting into the basepart 1 and for constituting the second joining location (e.g. accordingto any one of FIG. 1 to 3, 4, 5 or 6).

FIG. 16 illustrates a device according to aspect A of the inventionbeing a hip joint prosthesis, wherein the base part 1 constitutes theshaft of the prosthesis to be anchored in the femoral bone and the basedpart 2 is an intermediate prosthesis part, to which a further based part2′ (based on the based part 2 which is itself based on the base part 1,and constituting the ball section of the prosthesis). The joininglocations between base part 1 and based part 2 and between based part 2and further based part 2′ are shown without detail. However, eachmatched pair of joining locations comprises a first and a second joininglocation and is equipped to result after application of mechanicalvibration in a positive fit connection between a corresponding surfacestructure of the non-liquefiable material of the second joining locationand the liquefiable material of the first joining location having in aliquid state penetrated the named surface structure. Advantageous secondjoining locations for the device according to FIG. 16 are in particularstructures as shown in FIG. 4, however structures according to FIG. 1 to3 or 5 or 6 are also applicable.

It is possible also that all three or at least two of the parts 1, 2 and2′ of the prosthesis according to FIG. 16 are joined immediately beforeimplantation, i.e. by the surgeon and within the sterile space and thatthe assembled prosthesis is anchored as one part in the marrow space ofthe femoral bone.

FIGS. 17 to 20 show embodiments of a third group of exemplaryembodiments of aspect A of the invention. In this group of embodimentsthe based part 2 is joined to the proximal end of at least one base part1, wherein this proximal end protrudes from the opening in the bonetissue in which the base part 1 is anchored and wherein the assemblageof base part 1 and based part 2 serves for securing a further tissue(e.g. soft tissue) or a further device part and wherein the furthertissue or device part is fixed relative to the bone tissue in which thebase part 1 is anchored by the assemblage of the base part proximal endand based part 2. Instead of the named fixing function, the based partmay also serve for strengthening or stiffening the base part (FIG. 20).

FIG. 17 shows a device and a corresponding implantation method accordingto aspect A of the invention which serve for fixing a soft tissue part(e.g. tendon or ligament 31) or a further device part (e.g. supportingplate as used for osteosynthesis purposes) relative to bone. The basepart 1 is e.g. pin-shaped and consists of the liquefiable material. Itis anchored in an opening 10 in bone tissue 11 with the aid of theliquefiable material and mechanical vibration, such that its proximalend, which is e.g. pointed, protrudes from the opening 10. The tendon orligament 31 is then pushed against the proximal end of the base part 1such that this proximal end penetrates through the ligament or tendon 31which is either pre-perforated or not. The based part 2, which is formedas a sort of head for the base part 1 and, on its distal side, comprisesthe second joining location (preferably according to FIG. 7, pointeddistal end of base part serving as energy director), is then positionedon and joined to the proximal end of the base part 1 by applyingmechanical vibration to the head-shaped based part 2. As shown in FIG.17 an outer rim of the head-shaped based part 2 may comprise distallyprotruding sharp edges which, on joining the based part 2 to the basepart 1, are pressed into the tendon or ligament 31 and serve as furthermeans for retaining the tendon or ligament 31 relative to the bonetissue 11 in which the base part 1 is anchored.

FIG. 18 shows the same method and similar device parts as FIG. 16 usedfor securing an intervertebral element 50 (further device part), e.g. anintervertebral fusion element or cage, serving for fixing twoneighboring vertebral bodies relative to each other and to be securedbetween the two neighboring vertebral bodies 51. The positionedintervertebral element 50 is shown from a lateral side. It is positionedbetween the vertebral bodies 51 and then two or more than two pin-shapedbase parts 1 are anchored in the vertebral bodies above and below theintervertebral element 50. A substantially bar- or plate-shaped basedpart 2 is then joined to the proximal base part ends and moved towardsthe intervertebral element 50 to form together with the base parts 1 aclasp which lies against the face of the intervertebral element 50 andsecures it in its position between the vertebral bodies 51.

FIG. 19 shows a pin-shaped base part 1 which is anchored in bone tissue11 and comprises a proximal end projecting from the bone tissue andcomprises a groove 60 into which e.g. a suture 21 (or wire or rod) canbe snapped or positioned and in which the suture 21 is then secured byjoining the based part 2 to the proximal end of the base part 1 (matchedpair of joining locations e.g. according to FIG. 5)

FIG. 20 illustrates a further embodiment of aspect A of the invention,in which the base part 1 is an assembly of a base plate 55 which issecured to the surface of a bone by anchors 56 in the bone tissueextending through openings in the base plate 55 or being fixed to thebase plate side facing the bone surface. The base plate is preferablythin and in particular flexible in all directions. The based part 2 is aplurality of stiffening elements 57 to be joined to the one side of baseplate 55 facing away from the bone surface (proximal side). Either thebase plate 55 or the stiffening elements 57 comprise the first joininglocation (e.g. the base plate 55), the other one the second joininglocation (e.g. the stiffening elements 57), which is e.g. structuredaccording to FIG. 6 but may also be structured according to any one ofFogs 1 to 3, 4 or 5.

The flexible base plate is implanted e.g. across a bone fracture andflexibly adapted to the form of the corresponding bone surface. Theimplanted base plate is then stiffened preferably only locally dependingon the required stabilization of the fracture by correspondingly formedand positioned stiffening elements 57 (e.g. parallel stiffening stripesdistanced from each other, crosswise arranged stiffening stripes orstiffening plates). Advantageously the stiffening elements are flexiblealso and only the combination of base plate and stiffening element hasthe stiffness required for stabilizing the fracture. It may furthermorebe advantageous to make the base plate from a resorbable material suchthat stabilizing needs to be taken over gradually by the bone in whichthe fracture is healing (prevention of stress shielding).

Another or an additional advantage which can be achieved with anassembly as shown in FIG. 20 is the fact that the pins 56 and theopenings provided therefore in the base plate 55 can be covered with thestiffening elements 57. This is particularly advantageous if theassembly serves for replacing a bearing surface of a joint, e.g. of ajoint socket and one plate is used as stiffening element.

It is obvious for one skilled in the art to combine features of theabove described and illustrated embodiments of aspect A of the inventionin different ways and therewith to create further embodiments which arestill encompassed by the invention.

FIGS. 21 to 24 illustrate a first group of embodiments of aspect B ofthe invention. These embodiments encompass a device comprising a basedpart 2 and at least one base part 1 and a method for implanting thedevice in an opening provided in bone tissue by first positioning atleast a distal end of the based part in the opening and then pushing thebase part or the base parts between the bone tissue and the base partand thereby anchoring the base part in the bone tissue of the wall ofthe opening and simultaneously joining it to the based part. The basepart preferably consists of a liquefiable material and comprises thefirst joining location, which joining location is situated at a lateralside of the base part. The based part comprises preferably the secondjoining location, which is situated at a lateral side of the based part.The base part may also comprise a core of a non-liquefiable material andbe coated on one lateral side with the liquefiable material, wherein theopposite lateral side then constitutes the second joining location, thefirst joining location being arranged on the base part.

FIG. 21 shows a device according to aspect B of the invention, thedevice being a suture anchor. The device comprises a based part 2 and abase part 1 which are implanted in an opening 10 provided in bone tissue11. The base part 1 consists of the liquefiable material and on alateral side comprises the first joining location. The based part 2 ise.g. equipped with an eyelet (positioned e.g. on its proximal end) forfixing a suture or wire consists of a non-liquefiable material andcomprises on its lateral side the second joining location (e.g., asillustrated in any one of FIG. 1 to 3 or 4, 5, or 6). For implanting thedevice, the based part 2 is first positioned in the opening 10 providedin the bone tissue 11. The base part 1 is then pushed into the openingbeside the based part 2 on the one side thereof which comprises thesecond joining location. This pushing is accomplished with the aid of avibrating tool (not shown) which is applied to the proximal face of thebase part 1. Simultaneously with the pushing, mechanical vibration iscoupled from the tool into the base part. Due to the pushing motion thematched pairs of first and second joining locations are brought intocontact with each other and due to the mechanical vibration the basepart 1 is anchored on its one lateral side in the bone tissue of thewall of opening 10 and simultaneously joined on its other, oppositelateral side to the based part 2. This results in the based part 2 beinglaterally fixed relative to the bone tissue via the base part 1 and, inparticular if the base part has the shape of a wedge, also in the basedpart being pressed against the bone wall of the opening 10 on the sideopposite the base part.

In the embodiment illustrated in FIG. 21, the opening comprises anundercut region at least on its one side and the based part 2 comprisesa foot which fits into the undercut region. This design of opening 10and based part 2 serves as an additional means for retaining the basedpart 2 in the opening 10 but requires a correspondingly larger entranceto the opening, which is then filled by the base part 1.

FIG. 22 shows a further embodiment of aspect B of the invention, whereinthe implanted device serves again as a suture anchor and makes itpossible to fix the suture 21 relative to the bone tissue 11simultaneously with retaining the based part 2 with the aid of base part1. Again, for implantation, the based part 1 is introduced in theopening 10 provided in the bone tissue 11 and the base part 1 is thenpushed between the opening wall and the based part. Other than shown inFIG. 21, according to FIG. 22 the base part 1 comprises the secondjoining location on a side opposite its being anchored in the bonetissue and the base part 2 comprises the first joining location, whereinthe suture 21 extends across this first joining location and onliquefaction of the liquefiable material of this first joining locationis immersed in this material to be retained therein when itre-solidifies.

FIGS. 23 and 24 show embodiments of aspect B of the invention in whichmore than one base part 1 is used for fixing the based part 2 relativeto the bone tissue 11 of which a surface is visible. In both cases theproximal end of the based part 2 is shown to be equipped with a threadwhich is used for fixing a further device part to the based part. Theopening 10 in the bone tissue 11 which is provided for the implantationcan in both cases be a bore with a round cross section wherein for theembodiment shown in FIG. 23, the bore is lightly larger than acorresponding cross section of the based part 2, and for the embodimentas shown in FIG. 24 the bore has a same cross section as an outer crosssection of the based part, wherein this outer cross section encompassesconcave portions to which the shape of the base parts 1 is adapted.

FIGS. 25 to 32 show a second group of embodiments of aspect B of theinvention, wherein the based part is positioned relative to a bonesurface and the base part is pushed between the based part and the bonesurface for being simultaneously anchored in the bone surface and joinedto the based part.

FIG. 25 shows as a device according to the invention a based part 2whose distal end is equipped for being anchored in an opening in bonetissue with the aid of a liquefiable material and mechanical vibration.The opening 10 provided for the based part reaches e.g. across a bonefracture 65 from a first bone fragment 11.1 into a second bone fragment11.2, wherein the based part 2 is dimensioned to be only anchored in thesecond bone fragment 11.2. The based part 2 further comprises a proximalhead section 30 with a cross section larger than the cross section ofopening 10. The head section 30 and a core of the based part 2 arepreferably made of a non-liquefiable material and the head preferablycomprises a slanting under side which is equipped with a surfacestructure suitable as second joining location (e.g. according to any ofFIG. 1 to 3 or 4, 5, or 6. The based part 2 is anchored in opening 10and then at least one wedge-shaped base part 1 is pushed between thebone surface of the first bone fragment 11.1 and the head section ofbased part 2. Simultaneously the based part is vibrated by a vibratingtool applied to its proximal face. During such pushing and vibration,the base part 1 is not only on the one side joined to the head section30 of the based part 2 and on the other side anchored in the bone tissuebut also the two bone fragments separated by the fracture are pulledagainst each other. The bone surface in which the base part 1 is to beanchored may for such anchorage have been provided with a rough surface.

FIGS. 26 to 31 show further embodiments of aspect B of the invention,according to which aspect at least one base 1 part is pushed between abone surface and a based part 2 while being vibrated such that the basepart is simultaneously anchored in the bone tissue and joined to thebased part thereby fixing the based part relative to the bone tissue.All FIGS. 26 to 31 show applications concerning intervertebral implantsreplacement, wherein the intervertebral element (based part 2) and thebase part or base parts are implanted e.g. from the frontal side or froma lateral side of the vertebral column.

FIGS. 26 and 27 show an intervertebral element 50 (fusion element, e.g.cage) replacing a natural intervertebral disc and constituting the basedpart 2 of a device according to aspect B of the invention. Theintervertebral element 50 is shown positioned between two neighboringvertebral bodies 51 (FIG. 26, left: before placement of the base parts;right: after placement of the base parts) and viewed from above (FIG.27). The intervertebral element 50 is secured relative to the twovertebral bodies 51 with the aid of e.g. two upper and two lower baseparts 1 which are e.g. pin-shaped and comprise the liquefiable materialfor being able to be anchored in the bone tissue of the vertebral bodiesand constituting the first joining location. The base parts e.g. consistfully of the liquefiable material or comprise a core of anon-liquefiable material which is at least partly coated with theliquefiable material. In the latter case the core preferably protrudesat the distal end of the base part and there comprises a sharp point orself reaming edges.

The base parts are pushed between the vertebral body 51 and theintervertebral element 50 and are simultaneously vibrated by applying avibrating tool to their proximal face. For allowing such pushing in ofthe base parts 1 the outer cortical bone layer of the relevant regionsof the frontal or lateral side of the vertebral bodies 51 is removed andthe intervertebral element 50 comprises on its upper and lower face 53corresponding channels 54 with a ring shaped extension or other undercutstructures (second joining location, visible in FIG. 27). On pushing andvibrating the base part 1 between the vertebral body 51 and theintervertebral element 50 the liquefiable material of the base part 1 isliquefied and forced into the bone tissue of the vertebral body 51 onthe one side and into the ringshaped extension or other undercutstructures of the channel in the intervertebral element 50. This isillustrated on the right hand side of FIG. 26.

FIGS. 28 and 29 show the same application as FIGS. 26 and 27 (same viewas in FIG. 26). According to FIG. 28 the vertebral bodies 51 are shownto also comprise channels 54′ for introduction of the base parts 1. Thechannels advantageously have an undercut cross section and the baseparts have cross sections adapted to the undercut channel. According toFIG. 29 the intervertebral element 50 is equipped with regions 50′ of aporous material (e.g. a metal foam material) which can be penetrated bythe base parts 1 like the cancellous bone of the vertebral body 51 (seealso FIG. 3). Therefore, it may not be necessary to provide channels 45in the intervertebral element 50.

FIG. 30 shows a further exemplified embodiment of aspect B of theinvention and illustrates a further application of device and methodregarding intervertebral disc replacement. The intervertebral element 50(based part 2) has the form of a known intervertebral disc implant (nonfusion element) and, in the present embodiment, comprises not only adisc element 70 but also an upper and a lower retaining element 71 forkeeping the disc element 70 in place and to be fixed to the end platesof the vertebral bodies 51. The top of FIG. 30 shows part of the lowerretaining element 71 and one of the base parts 1 in a lateral section ofthe vertebral column before introduction of the base part 1, and belowthe assembled and implanted device in a section from the front side tothe dorsal side. The retaining elements 71 comprise back and front rims72 protruding against the vertebral body 51 such that when the retainingelement 71 is positioned on the vertebral body, there is a laterallyopen gap 73 between the endplate of the vertebral body 51 and theretaining element 71, into which gap the base part 1 is to be pushed.The one side of the retaining element 71 facing away from the discelement 70 is further equipped with a pattern of e.g. undercut cavitiesfor being able to function as second joining location (not shown).

The base part 1 comprises a core of a non-liquefiable material and ispartly coated with the liquefiable material, constituting the means foranchoring and the first joining location 6. Its distal end of thenon-liquefiable material is preferably equipped with self-reamingstructures 74. The base part may in this case also comprise a perforatedsleeve with the liquefiable material positioned therein, wherein thedistal end of the perforated sleeve comprises the self-reamingstructures (similar to FIG. 32).

The intervertebral element 50 including the disc element and theretaining elements 71 (based part 2) is positioned between twoneighboring vertebral bodies 51. Then upper and lower base parts 1 areintroduced between the retaining parts 71 and the vertebral body 51,i.e. into gaps 73, while the base part 1 is vibrated by application of avibrating tool to the proximal end of it. Introduction and simultaneousself reaming, joining to the intervertebral element and anchorage in thebone tissue of the vertebral body are thereby effected.

Preferably the vibrating tool used for pressing and vibrating the basepart 1 is designed for being able to hold one base part 1 such that itcan be used not only for application of mechanical vibration andpressure to the base part but also for positioning it in the firstplace.

FIG. 31 shows a further exemplary embodiment of aspect B of theinvention in an application regarding vertebral disc replacement (fusionelement). The device again comprises an intervertebral element 50 (basedpart 2) and a plurality of base parts 1 designed for securing the basedpart 2 relative to the bone tissue of two neighboring vertebral bodies51. The intervertebral element 50 is e.g. a cage-like structure of anon-liquefiable material which is filled with bone fragments or with abone replacement material. The openings of the cage structure and thebone fragments or bone replacement material constitute the secondjoining locations. The base parts 1 are staple-shaped and are e.g. madeof the liquefiable material, wherein the two distal ends of the basepart 1 are pushed between the intervertebral element 50 and the bonetissue of the vertebral body 51 and constitute on the one side the firstjoining location and on the other side the means for anchorage in thebone structure of the vertebral endplates. Advantageously, thestaple-shaped base part 1 has a further protruding area in its center,which is anchored in the intervertebral element on pushing the base part1 against the intervertebral element 50. The based part may alsocomprise a core of a non-liquefiable material which is at least partlycoated with the liquefiable material.

FIG. 31 shows the two vertebral bodies 51 and the intervertebral element50 therebetween from the front side. The base part 1 on the right handside is positioned for application of mechanical vibration and pressureusing a vibrating tool 12 (sonotrode). The base part 1 on the left handside is joined to the intervertebral element 50 and is anchored in thevertebral end plates.

FIG. 32 shows a further embodiment of aspect B of the invention, whereinthe device is to be fixed relative to a bone surface using a base partwhich is pushed between the bone surface and a based part of the device.The base part 1 of this embodiment comprises a wedge shaped sleevecomprising an inside channel 80 and openings connecting the channel 80with the outside surface of the sleeve (perforated sleeve). The sleevemay further comprise self-reaming teeth on the one side which is to beanchored in the bone tissue. The liquefiable material is positionedinside the channel 80. The bone surface may be the inside surface of atubular bone and the based part 2 may be a shaft of an endoprosthesis tobe fixed in the marrow space of this tubular bone. Implant and bone areshown only partly in FIG. 32.

For implantation, the base part 2 according to FIG. 32 is positioned inthe tubular bone and preliminarily retained by positioning thewedge-shaped base part 1, which is possibly pushed whereby theself-reaming teeth are worked into the bone tissue. The base part 1 isthen pressed further into the marrow space by applying a vibrating tool12 to the proximal surface of the liquefiable material which due to thepressure and vibration is at least partly liquefied and pressed throughthe openings to anchor the implant on the one side in the bone surfaceand on the other side in the structure of the second joining location(e.g. according to FIG. 5) of the based part on the other side. FIG. 32shows the preliminarily positioned wedge-shaped base part 1 on the leftside and the same device after application of pressure and vibration onthe right side.

The base part 1 according to FIG. 32 may comprise openings from thecentral channel to the surface of the sleeve only on its side facing thebased part 2 and being anchored in the bone surface with barbs or solelywith the aid of the self-reaming teeth or other suitable structures suchas e.g. barbs.

FIGS. 33 to 35 illustrate a third group of embodiments of aspect B ofthe invention which embodiments are similar to the first groupembodiments but for which the based part 2 is a further bone tissue partor consists of a bone replacement material.

FIG. 33 shows a bone-tendon graft 81 (based part 2) positioned in atunnel or bore 10 in bone tissue 11 and fixed within the tunnel or borevia base parts 1 which are pushed between the bone part of the boneregion of the graft 81 and the bone of the tunnel or bore wall. Thereinchannels 54 and or 54′ may be provided in either bone tissue. Dependingon the bone tissues to be joined via the base parts 1, it may bepossible to push the base parts 1 therebetween without the need ofchannels 54 and/or 54′. It is further possible to equip the base partsas earlier shown with a core of a non-liquefiable material andself-reaming structures e.g. on a distal end thereof (as e.g. shown inFIG. 30). In such a case the base elements will provide channels and itis not necessary to provide them beforehand.

FIG. 34 shows a similar application of aspect B of the invention inwhich a bone fragment 11.1 on one side of a bone fracture 65 is fixed toa bone fragment 11.2 on the other side of the fracture via a base part 1or a plurality thereof (in the language as used before: one bonefragment representing the based part 2 which is joined to the base part1 and the other bone fragment representing the bone tissue 11 in whichthe base part is anchored). Channels 54 and 54′ in the bone fragmentshave preferably an undercut cross section and the base parts 1 have acorresponding cross section. Such base part 1 is shown on the right handside of FIG. 34.

FIG. 35 shows a further embodiment of aspect B of the invention, whereina based part 2 of bone tissue is fixed in an opening 10 in bone tissue11 with the aid of a plurality of base parts 1 which are pushed betweenthe based part 2 and the wall of opening 10. Therein the based part 2may consist of autologous or homologous bone tissue or of a bonereplacement material and constitute a plug to fill an opening caused byharvesting bone tissue. On the other hand the bone material 11 mayconstitute an implant made of a bone replacement material and the plugmay be made of autologous bone tissue and serve for promoting ingrowthof bone tissue into the bone replacement material.

FIGS. 36 and 37 illustrate a further group of exemplary embodiments ofaspect B of the invention, wherein a base part 1 serves for joining twobased parts 2 and 2′ which may be fixed to bone tissue with the aid of aliquefiable material and mechanical vibration and wherein the base part1 is pushed between the two based parts and at the same time vibratedfor liquefaction of a liquefiable material comprised by the base part 1and for producing a positive fit connection between two opposite joininglocations of the base part 1 and matched joining locations on the towbased parts 2 and 2′.

FIG. 36 shows a further exemplified embodiment of aspect B of theinvention, wherein the device comprises a base part 1 and two furtherimplant parts (based parts 2 and 2′). The device is in particularsuitable as intervertebral element 50 for being implanted between twovertebral bodies 51 in order for the tow vertebral bodies to be fusedtogether and to be spaced from each other in a predefined manner. FIG.36 shows the base part 1 and the based parts 2 and 2′ in section beforeimplantation and assembly (above) and after implantation and assembly(below).

The two based parts 2 and 2′ are shaped as an upper and a lower wedge 82which wedges are equipped for being anchored in the end plates of thevertebral bodies 51 with the aid of a liquefiable material andmechanical vibration. The wedges 82 therefore comprise e.g. an insidechannel 80 originating from a proximal face and ending in a plurality ofmouths on the wedge surface to face the bone tissue of the vertebralbody. The wedges 82 (perforated sleeves in wedge form) are made of anon-liquefyable material and the liquefiable material is positioned inthe inside channels 80 and serves for anchoring the wedges 82 in thevertebral bone tissue.

The base part 1 to be pushed between the two based parts 2 and 2′ isalso wedge-shaped, comprises an inside channel 80 originating from theproximal face and ending in mouths on the surfaces to be in contact withthe wedges 82, and it is made of a non-liquefiable material, theliquefiable material e.g. in form of a pin being positioned in theinside channel 80 and serving for joining the base part 1 to the basedpart wedges 82.

The based part wedges 82 are positioned between neighboring vertebralbodies and are anchored therein. For achieving such anchorage,mechanical vibration and pressure is applied to the pin of liquefiablematerial by applying a correspondingly shaped vibrating tool (not shown)to the proximal face of this pin. The wedge-shaped base part 2 is thenintroduced between the based part wedges 40 and brought into a positionin which the distance between the vertebral bodies 51 is at the desiredvalue. Then mechanical vibration and pressure is applied to the pin ofliquefiable material in the inside channel 80 of the base part 1 byapplying a correspondingly shaped vibrating tool (not shown) to theproximal face of this pin. By doing so, the liquefiable material in thebase part 1 is at least partly liquefied and pressed through the mouthsfacing the based part wedges 82 (first joining location) to be pressedinto undercut structures provided on the based part wedges 82 (secondjoining location, e.g. according to FIG. 5 or 6).

A wedge system similar to the wedge system shown in FIG. 36 may comprisetwo wedges only which both are anchored in the bone tissue of thevertebral bodies on one side and are joined to each other on an oppositeside, this means an embodiment wherein the base part and the based partare substantially identical.

FIG. 37 shows a last embodiment of aspect B of the invention. Again morethen one based part 2, 2′ . . . is fixed relative to a bone surface withthe aid of a plurality of base parts 1 which are laterally joined to thebased parts 2 and at the same time are distally anchored in the bonetissue in which corresponding openings are provided. The based parts 2,2′ . . . are modular elements of a supporting plate which is e.g. usedfor osteosynthesis, in particular for fixing bone fragments 11.1 and11.2 on either side of a bone fracture 65 relative to each other. Asdiscussed in connection with FIG. 34 the lateral channels 54 provided atlateral sides of the plate elements preferably have undercut crosssections serving a second joining locations. The base parts 1 comprise across section which corresponds to two aligned channels 54 and are e.g.made of the liquefiable material or are coated therewith.

It is obvious for one skilled in the art to combine features of theabove described and illustrated embodiments of aspect B of the inventionin different ways and therewith to create further embodiments which arestill encompassed by the invention.

FIGS. 38 to 46 illustrate a first group of embodiments of aspect C ofthe invention, according to which a preferably pin- or plate-shaped basepart 1 comprising at its distal end a joining location and preferablybeing equipped for being anchored in bone tissue a its lateral sides, ispositioned through a corresponding through bore in bone tissue for itsdistal end to be in contact with the joining location of the based part2. By application of pressure and vibration to the proximal face of thebase part, the base part is anchored in the bone tissue of the tunnelwalls and simultaneously joined to the based part such securing the basepart relative to a surface of the bone tissue. If the base part is notequipped for being anchored in the bone tissue of the tunnel wall itneeds to be equipped with alternative means (e.g. a head) for beingretained in the tunnel.

FIG. 38 illustrates an exemplary embodiment of aspect C of theinvention. The device is e.g. an endoprosthesis for replacement of ashoulder joint to which a bone fragment 11.1 is to be fixed. Theendoprosthesis constitutes the based part 2 and a pin for fixing thebone fragment to the endoprosthesis is the base part 1. The bonefragment 11.1 is the bone tissue comprising a through opening 10. Thebase part 1 is equipped for being anchored in the bone tissue 11 of thebone fragment and preferably comprises the first joining location. Thebase part 1 is positioned through a proximal mouth of opening 10 for itsdistal end to get in contact with the joining location (preferablysecond joining location) of the based part 2 which is positioned againstthe distal mouth of the through opening 10. By applying pressure andvibration to the proximal face of the base part, the latter is anchoredin the wall of the opening and simultaneously joined to the based part2, i.e. the bone fragment is fixed relative to the endoprosthesis.

If the cross section of the through opening 10 is larger than the crosssection of the base part 1 and/or if the proximal part of the base partsdoes not comprise a liquefiable material, no anchorage of the base partmay occur or anchorage only in the region of the distal end thereof. Forsuch a case it is advantageous to equip the base part 1 with a headsection having a larger cross section which may be anchored on thesurface of the bone fragment in the region of the proximal mouth of thethrough opening 10.

The shoulder joint endoprosthesis (based part 2) as shown in FIG. 38e.g. consists of a non-liqiefiable material such as titanium or atitanium alloy and is fixed in a correspondingly prepared tubular bone45 using a known method such as e.g. cementing. The endoprosthesis ispreferably equipped with the second joining location, e.g. a surfacearea with a structure as shown e.g. in any of FIG. 1 to 3, 4, 5 or 6.The base part 1 advantageously consists completely of the liquefiablematerial or comprises a non-liquefiable core being coated with theliquefiable material at least in surface areas serving as first joininglocation (distal end) and surface areas for anchoring the base part inbone tissue with the aid of the liquefiable material and mechanicalvibration (lateral and/or proximal area).

For implanting the device according to FIG. 38, a through opening 10 isbored through the bone fragment 11.1. The fragment is then positionedagainst the endoprosthesis and possibly fixed temporarily using a clampor glue. The base part is then positioned in the opening 10, itsproximal end advantageously protruding therefrom. Mechanical vibrationand pressure are then applied to the proximal face of the base partusing e.g. a sonotrode with a distal face adapted to the proximal faceof the base part. Due to liquefaction of the liquefiable material of thebase part, the latter is simultaneously joined to the endoprosthesis andanchored in the bone tissue of the bone fragment 11.1.

The method as illustrated in FIG. 38 may be changed in various wayswhich leads to further embodiments of aspect C of the invention, such ase.g.:

-   -   The based part 2 (shoulder prosthesis) is equipped with the        first joining location, e.g. carries a coat of the liquefiable        material in surface areas to which bone fragments are likely to        be fixed and the pin-shaped base part 1 is equipped with the        second joining location, i.e. comprises in the area of its        distal end a non-liquefiable material and preferably one        undercut cavity or protrusion (e.g. according to FIG. 7).    -   The bone fragment 11.1 consists not of natural bone material but        is a piece of bone replacement material having a similar porous        structure as bone tissue which porous structure is suitable for        being penetrated by the liquefied material of the base part.    -   The base part 1 may be designed to be a protrusion of the        endoprosthesis and is anchored in the bone fragment by applying        pressure and vibration to the bone fragment.

FIG. 39 illustrates a intervertebral element 50 (intervertebral fusionelement, based part 2) positioned between two vertebral bodies 51 andcomprising a lateral or frontal region of a porous material, e.g. ametal foam material (second joining location according to FIGS. 1 to 3).The intervertebral element 50 is secured between the vertebral bodies bytwo pin- or plate-shaped base parts 1 which are secured in the throughopenings 10 (tunnels) extending through the bone tissue of the vertebralbodies and are anchored therein and in the porous region of theintervertebral element (upper base part shown before application ofpressure and vibration; lower base part shown after application ofpressure and vibration).

FIG. 40 shows an endoprosthesis (based part 2) suitable for resurfacinga concave bearing surface in a joint. The endoprosthesis is fixedrelative to the bone with the aid of base parts 1 which extend throughopenings in the bone tissue and are joined to an inner layer of theendoprosthesis which consists e.g. of a metal foam material (secondjoining locations according to FIGS. 1 to 3). For better anchorage ofthe base part on the bone tissue it is advantageous to design the basepart with a shoulder and the opening through the bone tissue with acorresponding step.

An endoprosthesis similar to the one shown in FIG. 40 may also replace aconvex bearing surface of a joint.

FIG. 41 illustrates a device for resurfacing of a facet joint accordingto aspect C of the invention. On the left of FIG. 41 the joint is shownin section with the bearing surface portions removed from the prosessusarticularis inferior and superior 83. In the middle of FIG. 41 thebearing surface replacement parts (based parts 2) are shown in the samesection, wherein the replacement parts comprise a porous inner section(metal foam constituting a second joining location as illustrated inFIGS. 1 to 3) and a full bodied outer layer constituting the bearingsurface and wherein the replacement parts are fixed by pin-shaped baseparts 1 which extend in openings extending through the bone tissue fromdorsal sides of the processi articulares to the inner surface of thereplacement parts (based parts 2) and are joined to the replacement partand preferably anchored in the bone tissue. The base parts 1 comprise ashoulder that is designed to reach the bone surface when the base partis pushed into the through opening and is able to be anchored in thisbone surface or form a head protruding from the bone surface. On theright of FIG. 41, the implanted endoprostheses are shown viewed in thedirection A as indicated in the section shown in the middle of FIG. 41.

FIG. 42 shows a further embodiment of aspect C of the invention. Thebase part 2 of this embodiment is a joint prosthesis for a small jointlike e.g. a finger or toe joint whose short stem is retained in acorresponding cavity provided in the epiphytic bone tissue of thecorresponding bone end by a plurality of preferably pin-shaped baseparts 1 which reach from opposite outside surfaces of the bone into thecavity and are laterally anchored in the bone tissue and distally joinedto the implant (based part 2). Furthermore, the base parts 1 may fillempty space between the stem of the based part and the bone tissue. Thebased part comprises e.g. second joining locations according to FIGS. 1to 3.

FIGS. 43 to 46 show a second group of exemplary embodiments of aspect Cof the invention, for which embodiments the based part 1 is positionedin the marrow space of a tubular bone 45 and the base part 1 reachesfrom the outside of the tubular bone through the bone tissue of thetubular bone wall to the based part. For anchoring the base part in thewall of the tubular bone consisting of cortical bone tissue it may beadvantageous to provide suitable structures in the opening through thebone wall.

FIG. 43 shows a marrow nail or marrow plate 85 being fixed in the marrowspace 86 of a tubular bone 45 with the aid of a plurality of preferablypin-shaped base parts 1 which preferably consist of the liquefiablematerial and which extend from the outside surface of the tubular bone45 to the marrow space through openings 10 through the bone wall of thetubular bone to the marrow nail or plate 85. Such marrow nails or plates85 are used for e.g. stabilizing a fracture of the tubular bone 45.

For implanting the device, openings 10 are provided and the marrow nailor plate 85 is introduced into the marrow space and possiblypreliminarily retained with suitable means. The base parts 1 are thenintroduced into the openings 10 such that their distal end is in contactwith the marrow nail or plate. Pressure and vibration applied to theproximal face of the base part results in joining the distal base partend to the marrow nail or plate 85 and possibly anchoring the base partin the bone wall of the tubular bone 45.

For embodiments as shown in FIG. 43 it may be that a space between thebased part and the bone wall of the tubular bone in the region of thethrough opening provided for the base part has a shape, that when filledwith the liquefiable material constitutes enough geometrical retentionfor a second joining location (similar to the one illustrated in FIG. 7)such that provision of a specific surface structure serving as secondjoining location may not be necessary.

FIG. 44 shows a similar embodiment as FIG. 44. Instead of a joininglocation, the marrow nail or plate 85 comprises a through openingthrough which the base part 1 reaches to be in contact with the oppositewall of the tubular bone 45 to which wall the base part 1 is joined bybeing anchored therein. This means that in the embodiment according toFIG. 44 the opposite wall of the tubular bone 45 constitutes in thesense of the invention the based part 2.

Instead of a marrow nail or marrow plate 85 as illustrated in FIGS. 43and 44, the based part of a similar embodiment may also be the shaft ofa joint prosthesis which is to be retained in the marrow room of atubular bone.

FIG. 45 shows a preliminarily flexible marrow nail 85 (based part 2)having the form e.g. of a link chain comprising links which are joinedto each other in an articulate manner. As detailed in connection withthe previously discussed embodiments of aspect C of the invention, thechain constitutes the based part 2 and each chain link or connectingelement between chain links comprises a joining location which is fixedrelative to the tubular bone in which the chain is positioned by beingjoined to the distal end of a preferably pin-shaped base part 1 reachingthrough the wall of the tubular bone 45 into the marrow space thereof tocontact the chain. The preliminarily flexible chain can be introducedinto the marrow space using considerably less room than introduction ofa rigid marrow nail and when joined to the base parts 1 represents arigid marrow nail having sufficient mechanical strength for itsfunction.

FIG. 46 shows a further embodiment of aspect C of the invention. Thecorresponding device again serves e.g. for stabilizing bone fragments11.1 and 11.2 of a tubular bone 45 on two sides of a bone fracture 65.Other than in the previously discussed embodiments of aspect C the basepart 1 and the based part 2 are quite similar, i.e. both are preferablypin-shaped and comprise the liquefiable material. The based part 2 isfirst introduced through an opening 10 in the bone wall such that itsdistal end reaches the opposite bone wall. With the aid of mechanicalvibration and the liquefiable material, the based part 2 is anchored inthe opening 10 and preferably on the inside surface of the opposite bonewall. The base part 1 is then introduced through a corresponding opening10 which is positioned and oriented such that on introduction the basepart 1 meets with the based part 2 in the marrow space before reachingthe opposite bone wall. Pressure and vibration applied to the proximalend of the base part 1 results in anchoring the base part in the opening10′ and on the inside surface of the opposite bone wall as well as injoining the base part 1 to the based part 2 where they meet. For suchjoining, one of the parts is equipped with a second joining location,e.g. with a structured sleeve lining an opening in the based part 2through which opening the base part 1 is introduced on meeting the basedpart.

FIGS. 47 and 48 illustrate a second group of embodiments of aspect C ofthe invention. In these embodiments the again preferably pin-shaped basepart 1, instead of being introduced through an opening in bone tissue,is introduced through an opening in a further device part for its distalend to be joined to the based part 2.

In the example as illustrated in FIG. 47, the further device part ise.g. a prosthetic tibia plateau 87 but may also be part of anotherorthopedic implant, e.g. for resurfacing another joint. The base part 1serves for fixing a bone fragment (based part 2) or a correspondingpiece of bone replacement material under the prosthetic tibia plateau87, which both constitute porous non-liquefiable materials suitable fora second joining location (in the sense as e.g. illustrated in FIG. 1 to3 or 4, 5, or 6). The base part 1 preferably consists of the liquefiablematerial, which, with the aid of mechanical vibration coupled into theproximal end of the base part 1, is liquefied and joined on the one handto the base part 2 and to the tibia plateau. For the latter purposes theopenings in the tibia plateau comprise inner surfaces equipped forforming a positive fit connection with the liquefiable material whenre-solidified.

The prosthetic tibia plateau 87 is fixed in the place of the naturaljoint socket to be replaced using a per se known method, wherein thebone fragment (based part 2) is positioned thereunder before or afterfixing the prosthetic plateau. The base part 1 (or a plurality of baseparts) is positioned in the openings of the tibia plateau 87 and thenmechanical vibration and pressure is applied to the proximal face of thebase part. The base part 1 is therewith anchored in the bone fragmentand simultaneously joined to the base part 1. It is possibly notnecessary to provide a bore in the bone fragment for anchoring the basepart 1 therein.

In the example as illustrated in FIG. 48 the further device part is anintervertebral element 50 for being positioned between to vertebralbodies 51 to replace an intervertebral disc or for fusing the twointervertebral discs. The based part is in this case the vertebral body51 adjoining the intervertebral element 50. The intervertebral elementis e.g. made of a non-liquefiable material and comprises at least onethrough opening whose proximal mouth is accessible from a front orlateral side of the vertebral column and whose distal mouth openstowards the bone tissue of the vertebral body 51. The through openingdoes not have a straight axis but a bent one, wherein the angle betweenthe proximal part of the opening and the distal part is between 110 and160 degrees or preferably between 135 and 150 degrees.

The intervertebral element 50 is positioned between two neighboringvertebral bodies 51. The base part 1 which is again preferablypin-shaped and consists of the liquefiable material is introduced intothe opening in the intervertebral element 50 from the proximal mouth tothe opening. It is then pressed towards the distal mouth of the openingand vibrated by a vibrating tool applied to its proximal end andtherewith firstly bent to accommodate the bend in the opening andsecondly anchored in the bone tissue of the vertebral body 51. The bendin the opening 10 and the base part 1 being bent accordingly suffice aspositive fit connection for retaining the intervertebral element 50 inits position between the vertebral bodies 51.

It is obvious for one skilled in the art to combine features of theabove described and illustrated embodiments of aspect C of the inventionin different ways and therewith to create further embodiments which arestill encompassed by the invention.

FIGS. 49 to 61 illustrate aspect D of the invention, according to whichthe device comprises a plurality of device parts which are pre-assembledsuch that they are moveable relative to each other in a limited manner,pre-assemblage being carried out in situ (in the implantation site) orex situ. The pre-assembled device positioned in the implantation site isadapted to this site by further relative movement of the device parts togive the device a site-specific configuration which is then fixed byjoining the device parts relative to each other. For this purpose thedevice parts are equipped with matched pairs of joining locations. Thedevice parts are joined by pressing them against each other and byapplying mechanical vibration to selected ones of them. Therein selectedones of the device parts may be further equipped for being anchored inbone tissue such representing base parts in the sense of the invention.However, this is not a condition for aspect D of the invention.

FIGS. 51 to 54 illustrate a first group of embodiments of aspect D ofthe invention. In these embodiments pairs of the device parts comprisematched pairs of first and second joining locations which, for fixingthe site-specific configuration of the device, are joined together byapplication of mechanical vibration to one device part of the pair.

FIGS. 49 and 50 show an exemplary embodiment of aspect D of theinvention. The corresponding device is a multi-part device comprising aplurality of device parts 90 being pre-assembled. The device in itspre-assembled configuration (FIG. 49 top) is a flexible chain of aplurality of device parts which are arranged to form in the implantedand assembled configuration e.g. an arc- or ring-shaped device anchorede.g. in the end plate of a vertebral body 51 and serving for retaining anatural or artificial intervertebral disc 50 or part thereof (FIG. 49below: viewed from the side; FIG. 50: viewed from above).

The device parts 90 of the embodiment according to FIGS. 49 and 50 areall identical or quite similar and substantially all of them constituteat the same time a base part 1 and a based part 2. Each one of thedevice parts is (as base part 1) anchored in the bone tissue of thevertebral body 51 and joined to a neighboring device part (based part 2)part in preferably one only step of applying pressure and vibration. Thenamed neighboring device part serves as base part in a following step ofapplying pressure and vibration.

All device parts 90 are equipped with a first and a second joininglocation 3 and 6 or alternating with two first or two second joininglocations and they are further equipped with a contact location 7 andwith liquefiable material positioned for anchoring the device part inthe bone tissue. The pairs of matched joining locations are arranged onsides of the device parts which face each other. The parts have, asshown in FIG. 49, e.g. a trapezoidal form and the chain of device partscan be formed into a circle in which each part is in contact with andeventually joined to two neighboring device parts.

The flexible chain of preliminarily assembled device parts 90 as shownon the top of FIG. 49 is brought to the implantation site by e.g.minimal invasive surgery. The chain is very suitable for such surgery asit is flexible and may be realized having a much smaller cross sectionthan the device in its implanted and finally assembled state shown inthe bottom part of FIG. 49 and in FIG. 50. The chain is then positionedand implanted and assembled part after part. FIG. 49 (bottom) showsthree positioned, implanted and assembled device parts forming animplant having the shape of an arc. FIG. 50 shows a correspondingring-shaped device of eight device parts.

As vibrating tool for assembling the links of the chain shown in FIG.49, a vibrating cable is applicable. The cable passes in the directionof the chain length through all chain links and its one end protrudesfrom the most distal one of the chain links. For pre-assembling thechain in a circle as illustrated in FIG. 50, the one cable endprotruding from the most distal chain link is brought near the mostproximal chain link and possibly slideably fixed to the cable protrudingfrom the most proximal chain link, to form a chain ring having a stillvariable form. The proximal end of the cable is connected to a vibrationsource (e.g. ultrasonic device) and is then pulled away from the chainring which is held in position with suitable means. Thereby the chainring diameter is brought to a minimum and the links are pressed againsteach other. This pressure and the vibration of the cable result in thelinks being connected to each other by the matched pairs of joininglocations being joined. If the cable has a surface structure which canfunction as a second joining location, the cable is at the same timejoined to the inside of the links and a cable ring, when separated fromthe proximal rest of the cable can remain in the chain to form a furtherdevice part stabilizing and strengthening the chain ring.

FIG. 51 shows a further multi-part device according to aspect D of theinvention. The device comprises four device parts 90, which arepre-assembled in an articulating harmonica-like manner, wherein thedevice parts in the region of the articulating connections are equippedwith matched pairs of first and second joining locations. The deviceserves e.g. for stabilizing two bone fragments 11.1 and 11.2 on eitherside of a bone fracture 65. For implanting the device, one of the fourpre-assembled device parts 90 is fixed on either side of the fracture65, e.g. by pins 91 which are anchored in the bone tissue of each bonefragment 11.1 and 11.2. The bone fragments or the fixed device partsrespectively are then pressed against each other for closing thefracture 65 and the articulating connections between the device parts 90are locked with the aid of mechanical vibration applied to each one ofthe connections.

It is possible to equip the device parts 90 of the device according toFIG. 51, which are situated nearer the bone tissue with pin-shapedprotrusions facing towards the bone surface and comprising a liquefiablematerial. These protrusions can then be anchored in the openings in thebone tissue provided for such anchoring. Such equipped device parts thenfunction as base parts in the sense of the earlier described aspects ofthe invention which base parts are simultaneously fixed to anotherdevice part (based part) and anchored in the bone tissue.

FIGS. 52 and 53 show further embodiments of aspect D of the invention.The three-part devices comprise a plate 20, applicable in osteosynthesise.g. for stabilizing a bone fracture, and an insert 92 comprising with athrough bore and being mounted in a through opening of the plate 20 tobe capable to be oriented in different directions relative to the plate.The device further comprises a pin part 93 adapted in cross section tothe opening in the insert 92. For implantation the plate 20 ispositioned relative to a bone surface, the bone surface is provided withopenings for the pin part by introducing a drill through the insertopening thereby orienting the insert 92 in a site-specific way and thenintroducing the pin part 93 through the opening in the insert 92 intothe opening in the bone surface and applying pressure and vibration toits proximal face to firstly anchor the pin part 93 in the bone tissueand to secondly join the insert 92 to the plate 20 to fix it in thesite-specific orientation.

According to FIG. 52, the bowl-shaped opening reaching through the plate20 and the insert 92 formed as a half sphere comprise second joininglocations each and the pin part 93 comprises a head region 94 consistingof a liquefiable material which material on pressing the pin part 93into the openings is pushed between plate 20 and insert 92 to constitutefirst joining locations on either side and to fix the insert 92 relativeto the plate 20.

According to FIG. 53 the pin part 93 and the plate 20 comprise theliquefiable material (first joining location) and the sphere-shapedinsert 92 comprises the second joining location, preferably on surfacesfacing the plate and on surfaces facing the pin part 93.

On pressing the pin part 93 extending through the opening in insert 92into the opening in the bone tissue and vibrating it by applying avibrating tool to its proximal face, the pin part is anchored in thebone tissue, the insert is joined in its site-specific orientation tothe plate 20 and the pin part 93 is joined to the insert 92.

FIG. 54 shows a further pre-assembled device comprising a plate 20 (e.g.suitable foe osteosynthesis purposes) and means for fixing the platerelative to a bone surface. The plate 20 comprises a non-liquefiablematerial and within this material grooves 96 running across theplate-side facing away from the bone surface. The grooves are preferablyundercut and comprise an inside surface suitable as second joininglocations (e.g. rough surface, microgrooves). The means for fasteningthe plate 20 relative to bone tissue are staple-shaped device parts 97e.g. comprising a metal wire as a core, which metal wire is at leastpartially coated with a liquefiable material except for the end regionswhere the metal core protrudes the coating and comprises cutting pointsor edges. The middle section of the staple-shaped device parts 97 has across section adapted to the groove cross section and a length greaterthan the groove length such that this middle section of thestaple-shaped device part 97 can be snapped into one of the grooves andbe pivoted therein (double arrow), such that the angle between the plate20 and the staple-shaped device part 97 is freely selectable.

The arrangement of plate and pivoting staple-shaped device partconstitute the pre-assembly. For fixing this pre-assembly relative tothe bone surface the staple ends are forced into the bone tissue byapplying pressure and mechanical vibration to the staple-shaped devicepart 97. This results in anchoring the side sections of the staple inthe bone tissue and in joining its middle section to the plate 20.

FIGS. 55 to 61 illustrate a second group of embodiments of aspect D ofthe invention, in which the device, apart from the pre-assembly ofdevice parts or the plurality of device parts designed for beingpre-assembled, comprises at least one additional device part (lockingpart 100) which comprises a liquefiable material and is designed forbeing introduced between second joining locations facing each other inthe pre-assembly of device parts. The site-specific configuration of thepre-assembled device parts is fixed by forcing the liquefiable materialof the locking part (100) between the second joining locations of thepre-assembled device parts, wherein this material constitutes twoopposite first joining locations matched to the second joining locationsof the pre-assembled device parts.

The movement of the pre-assembled device parts relative to each other,which movement is to be blocked by the locking part 100 is in particulara rotation and/or an axial displacement of a rod or bar (moveable part101) in a bearing opening in a bearing part 102 or formed by a pluralityof bearing parts 102. Therein the bearing part 102 and/or the moveablepart 102 comprise second joining locations facing each other when themovable part 101 is positioned in the bearing of the bearing part 102.The locking part 100 comprises the liquefiable material at a distal end.It is introduced through the bearing part 102 to contact the moveablepart 101 and on application of pressure and mechanical vibration to itsproximal face, the liquefiable material of its distal end is liquefiedand pressed between the bearing part 102 and the moveable part 101constituting on two opposite sides a first joining location matched tothe two second joining location. On re-solidification the liquefiablematerial locks the moveable part 101 relative to the bearing part orparts 102.

FIGS. 55 and 57 show the principle of the above referred to locking of arotation and/or axial displacement of a rod (moveable part 101). TheFigures are sections through bearing parts 102 and movable part 101 in adirection perpendicular to the rotation axis. Both bearing and movablepart comprise in the sense of second joining locations depressions (ase.g. illustrated in FIG. 1-3, 4, 5 or 6). The space between bearing part102 and moveable part 101 is accessible for the locking part 100, e.g.by the bearing part 102 comprising a corresponding opening leading fromits outer surface to its bearing surface.

FIG. 55 shows two bearing parts 102 being connected in any suitablemanner to close the bearing surface around the moveable part 101. Forlocking the moveable part 101 in a desired rotation and axial positionrelative to the bearing parts, the locking part 100 is introduced intothe opening of the bearing part (left hand side of FIG. 55) and, byapplying a vibrating tool to its proximal face, the locking part isvibrated and pressed against the surface of the movable part for theliquefiable material to be liquefied in the region of the distal end ofthe locking part and to be pressed between bearing parts and moveablepart and into the structures serving as second joining locations(depressions). On re-solidification of the liquefiable material,rotation and/or axial displacement of the movable part 101 are preventedby the positive fit connection between the movable part 101 and thebearing parts 102 which positive fit connection is realized on oppositesides of the correspondingly shaped liquefiable material of the lockingpart (locked configuration: right hand side of FIG. 55).

Depending on the surface structures serving as second joining locations,the movable part 101 is locked regarding rotary and/or axial loads.Experiments using a bearing opening of 5.9 mm inner diameter and a rod5.8 mm diameter being locked using a PLDLLA pin show good lockingcharacteristics against axial displacement with annular grooves andagainst rotation with axial grooves. Good locking is achieved in bothdirections if the surface structure on the movable part 101 and thebearing parts 102 comprise a pattern of depressions or a combination ofaxial grooves or blind bores and ring-shaped grooves.

The locking principle as detailed above is achievable for axial loadsonly in the same manner for movable parts with other then round crosssections.

FIG. 56 shows a further embodiment of the locking according to aspect Dof the invention, which locking in this case is reversible, if theconnection between the bearing parts (e.g. threaded bolts in threadedbores 103) is reversible and if the liquefiable material of the lockingpart 100 does not wet the bearing surfaces and therefore does not adhereto these on re-solidification. For achieving reversibility of thelocking, the structures of the second joining locations do notconstitute undercuts in the direction, in which the bearing parts are tobe separated from each other or constitute only small undercuts in thisdirection. Such structures are e.g. axial extending grooves whose crosssection extends parallel to the bolts and bores 103 into the bearingsurfaces of the bearing parts (as shown in FIG. 56) and relatively smallstructures (e.g. surface roughness) on the movable part 101. Obviouslycircular grooves as mentioned above are suitable for a reversiblelocking as illustrated in FIG. 56.

For loosening the connection between bearing parts 102 and movable part101, the bolts 103 are loosened and the liquefiable material is removedto release the moveable part 101.

FIGS. 57 to 61 show exemplary applications of the locking principleaccording to aspect D of the invention.

FIGS. 57 and 58 show a rod lock application for fixing a rod (moveablepart 101) to neighboring vertebral bodies 51 in order to support thevertebral column and maintain desired distances between the vertebralbodies. The rod locking device is substantially the device according toFIG. 56, wherein the non removable bearing part is equipped with aprotrusion 105 which is e.g. equipped for the locking device to beanchored in a corresponding bore provided in the vertebral body. FIG. 57shows the locking device closed around the rod in a larger scale andFIG. 58 shows the locking device mounted to a vertebral body.

FIG. 59 shows an external fixation device for stabilizing the fragmentsof a tubular bone 45 on both sides of a bone fracture 65. The devicecomprises supports 110 anchored with suitable means in the bonefragments and a rod 111 which connects the supports 111 to form togetherwith them the exterior device. Between supports 110 and rod 111 doublelocking devices 112 are provided. A first bearing part 102.1 bears thesupport 110 and defines the axial and rotary position of the lockingdevice relative to the support. A second bearing part 102.2 bears therod 111 and defines the axial and rotary position of the rod relative tothe support. A third bearing part 102.3 bears an axel of the firstbearing part 102.1 and defines an angle between the support and the rod.The whole external fixation device is pre-assembled in situ. When allparts are assembled their relative positions and orientations are lockedby introducing locking parts at all locations indicated with an arrow.

FIG. 60 shows a further application of a device which is similar to thedevice shown in FIG. 59 and serves for stabilizing a vertebral columnand maintaining defined distanced between vertebral bodies 51. Thesupports in this case are pedicle screws.

FIG. 61 shows in more detail a strikingly simple embodiment of a lockingdevice according to aspect D of the invention. The device comprises alocking part 100, which preferably consists of the liquefiable materialor is coated therewith, and which is anchored in bone tissue 11 with theaid of mechanical vibration. The locking part 100 comprises a shoulderon which a vibrating tool for its anchorage is applied and a protrudingsection of a smaller cross section. The bearing part 102 which ispreferably made of a non-liquefiable material comprises an inner bearingsurface and an opening leading to this bearing surface which opening isadapted to the protruding section of the locking part 100. The outersurface of the bearing part 102 around the opening is equipped forconstituting a second joining location 6 (e.g. as illustrated in FIG. 6.The bearing part 102 is preliminarily positioned on the protrudingsection of the locking part 100 and the movable part 101 is introducedin the bearing part 102. The site-specific rotary and/or axial positionof the movable part is established and then the bearing part is pushedtowards the bone surface and simultaneously vibrated, whereby theprotruding section of the locking part 100 is pushed against themoveable part 101, its liquefiable material is liquefied and penetratesbetween the moveable part 101 and the bearing part 102 to lock these twoon re-solidification. At the same time, the end of the bearing part 102which faces the bone surface is pressed into the shoulder of the lockingpart 100 and is joined to the latter in the sense of a further pair ofmatched first and second joining locations.

Instead of or in addition to the above described joining of the bearingpart 102 to the locking part 100 via the shoulder of the locking part,it is possible also to equip the inside of the bearing part opening forthe protruding section of the locking part 100 as second joininglocation and effect there a joint between the two parts.

It is obvious for one skilled in the art to combine features of theabove described and illustrated embodiments of aspect D of the inventionin different ways and therewith to create further embodiments which arestill encompassed by the invention.

FIGS. 62 to 64 illustrate aspect E of the invention, according to whicha plurality of device parts is brought independently to the implantationsite to be joined in the implantation site to form the complete device.The device parts are equipped with matched pairs of first and secondjoining locations, they are positioned in the implantation site suchthat the joining locations of a matched pair are facing each other. Thedevice parts are then joined to each other by being pressed against eachother and by applying mechanical vibration to one of them. Thereinselected ones of the device parts may be further equipped for beinganchored in bone tissue with the aid of a of a liquefiable material andmechanical vibration such representing base parts in the sense of theinvention. However, this is not a condition for aspect D of theinvention.

FIG. 62 shows a first exemplary embodiment of aspect D of the invention.The device is a intervertebral element 50 (fusion element, e.g. cage) tobe implanted between two vertebral bodies 51. The intervertebral element50 comprises two halves 50.1 and 50.2, wherein each one of the halvescomprises one of the joining locations of the matched pair thereof onthe side where they are to be joined. The advantage of theintervertebral element according to FIG. 62 as compared with a one-pieceintervertebral element is the fact that the element halves can beintroduced between the vertebral bodies from dorsal-lateral sides(arrows), from where they can be pressed against each other as well. Thepair of matched joining locations may be as illustrated in any one ofFIG. 1 to 3, 4, 5, or 6.

FIG. 63 shows a second exemplary embodiment of aspect D of theinvention. The device is a marrow nail 85 or plate which comprises e.g.three device parts to be introduced into the marrow space 86 of atubular bone 45 in succession and to be assembled therein in tow joiningsteps. The first nail part 120 comprises e.g. a core of non-liquefiablematerial and a coat of liquefiable material and is anchored in thecancellous bone of the bone end with the aid of the liquefiable materialand mechanical vibration and on the opposite face comprises a firstjoining location (coat) and a second joining location (core). The seconddevice part comprises e.g. a core of liquefiable material and a coat ofnon-liquefiable material and on both end faces comprises a first andsecond joining location. The third device part substantially correspondsto the first device part and when introduced and joined to the seconddevice part may be anchored in the diaphysic bone tissue of the boneend.

Due to the reduced length of the device parts of the nail 85 accordingto FIG. 63 compared with the complete length of the nail, a much smallerlateral opening in the bone is necessary for introducing the nail or itsparts respectively than is the case for a known complete nail.

FIG. 64 shows a modular plate (top: arrangement of four plate modules127 viewed from above; bottom: arrangement of two plate modules 127 insection) according to aspect D of the invention. The plate modules 127are fixed to a bone surface with the aid of pins 91 which reach throughbores of two superimposed plate modules and may be anchored in the bonetissue with the aid of a liquefiable material and mechanical vibration.Each plate module comprises at least two bores. The plate modulescomprise in the area of the bores for the pins on one side a firstjoining location 5 and on the other side a second joining location 6.This is realized e.g. by plate modules comprising a layer of aliquefiable material and a layer of a non-liquefiable material, whereinthe latter layer comprises a surface structure suitable for a secondjoining location, as e.g. shown in FIG. 5 or 6.

The modules are pre-arranged on the bone surface one after the other bydrilling suitable openings for successive modules and positioningsuccessive pins in the openings. When the whole plate is assembled andpreliminarily fixed, the pins 91 are driven into the bone openings byapplying mechanical vibration to their proximal face and are therewithanchored in the bone tissue. At the same time the plate modules 127 arejoined together to stiffen and stabilize the modular arrangement.

It is obvious for one skilled in the art to combine features of theabove described and illustrated embodiments of aspect E of the inventionin different ways and therewith to create further embodiments which arestill encompassed by the invention.

It is also obvious for one skilled in the art to use specific featuresof devices described in connection with one of the aspects of theinvention in embodiments according to any other aspect of the invention.

What is claimed is:
 1. An intervertebral element for being implantedbetween two vertebral bodies in order for the two vertebral bodies to befused together and to be spaced from each other, the intervertebralelement comprising: a first part being equipped for being positionedrelative to a first one of the vertebral bodies, and a second part beingequipped for being positioned relative to a second one of the vertebralbodies, and a further part, the further part being capable of beingmoved relative to the first and second parts when the first and secondparts are positioned relative to the vertebral bodies, and therebymoving the first and second parts away from each other until a distancebetween the vertebral bodies is at a desired value, wherein the furtherpart is equipped for being secured relative to the first and secondparts when the distance is at the desired value.
 2. The intervertebralelement according to claim 1, wherein the first part or the second partor both forms/form a wedge, whereby the first and second parts arecapable of being moved away from each other by the further part beingpushed between the first and second parts.
 3. The intervertebral elementaccording to claim 2, wherein the first part and the second part eachare a wedge, both being capable of being positioned against the bonetissue of the vertebral bodies on one side and of lying against thefurther part on an opposite side.
 4. The intervertebral elementaccording to claim 3, wherein the first part and the second part aresubstantially identical.
 5. The intervertebral element according toclaim 1, comprising a fixation mechanism for fixing the position of thefurther part relative to the first and second parts when the distance isat the desired value.
 6. The intervertebral element according to claim5, wherein the fixation mechanism is capable of fixing the further partrelative to the first and second parts at different relative positions.7. The intervertebral element according to claim 6, wherein thedifferent relative positions are continuously variable within a range.8. The intervertebral element according to claim 5, wherein the furtherpart is capable of being fixed relative to the first and second parts bya positive-fit connection.
 9. The intervertebral element according toclaim 8, wherein the further part comprises a further part insidechannel originating from a proximal face and ending in at least onesurface portion to be in contact with at least one of the first andsecond parts, the intervertebral element further comprising a materialliquefiable with the aid of mechanical vibration capable of beingpositioned in the further part inside channel for being liquefied andbeing pressed into structures of the respective first/second part toyield, after re-solidification, a positive-fit connection between thefurther part and the respective first/second part.
 10. Theintervertebral element according to claim 1, wherein at least one of thefirst part and of the second part is capable of being secured relativeto the vertebral body by a positive-fit connection.
 11. Theintervertebral element according to claim 10, wherein at least one ofthe first part and of the second part is capable of being anchoredrelative to the respective vertebral body by the positive-fitconnection.
 12. The intervertebral element according to claim 11,wherein at least one of the first part and of the second part is capableof being anchored relative to the respective vertebral body by a solidmaterial liquefiable with the aid of mechanical vibration, by pressingthe liquefiable material, in a flowable state, into bone tissue of thevertebral body to anchor, whereby after re-solidification of theliquefiable material, the first/second part is anchored relative to therespective vertebral body
 13. The intervertebral element according toclaim 12, wherein the first and second parts for being anchored relativeto the bone tissue comprise an first/second part inside channeloriginating from a proximal face and ending on a surface portion to facethe bone tissue of the vertebral body, the intervertebral elementfurther comprising the material liquefiable with the aid of mechanicalvibration capable of being positioned in the first/second part insidechannel for being liquefied and being pressed into bone tissue of thevertebral body to anchor, after re-solidification, the first/second partrelative to the respective vertebral body.
 14. The intervertebralelement according to claim 1, wherein the first and second parts aremade of a non-liquefiable material.
 15. The intervertebral elementaccording to claim 1, wherein at least one of the first and second partscomprises a structured, uneven surface portion facing the further part.16. The intervertebral element according to claim 15, wherein thestructured, uneven surface portion comprises undercut structures. 17.The intervertebral element according to claim 1, wherein the furtherpart is equipped for being fixed relative to the first and second partswhen the distance is at the desired value, the desired value beingfreely and continuously adjustable in an adjustment range.
 18. Anintervertebral element for being implanted between two vertebral bodiesin order for the two vertebral bodies to be fused together and to bespaced from each other, the intervertebral element comprising: a firstpart being equipped for being anchored in a first one of the vertebralbodies, and a second part being equipped for being anchored in a secondone of the vertebral bodies, wherein the intervertebral element forms awedge system in which the first and second parts are capable of beingdistracted relative to one another by a relative movement of parts untila distance between the two vertebral bodies is at a desired value, andwherein the first and second parts are equipped to be fixed relative toone another.
 19. The intervertebral element according to claim 18,wherein the first and second parts are equipped to be fixed relative toone another by a positive-fit connection.
 20. The intervertebral elementaccording to claim 18, wherein the first part and the second part eachare a wedge, both being capable of being anchored in the bone tissue ofthe vertebral bodies on one side and of being joined to the other parton an opposite side, whereby the first and second parts are capable ofbeing distracted by being moved relative to one another.
 21. Theintervertebral element according to claim 18, further comprising awedge-shaped base part, the base part being configured to be pushedbetween the first and second parts to distract the first and secondparts relative to one another, wherein fixing the first and second partsrelative to one another comprises a connection of the first part withone side of the base part pushed between the first and second parts anda connection of the second part with an other side of the base partpushed between the first and second parts.
 22. A method of implanting anintervertebral element between two vertebral bodies in order for the twovertebral bodies to be fused together and to be spaced from each other,comprising the steps of: providing the intervertebral element, theintervertebral element comprising a first part being equipped for beingpositioned relative to a first one of the vertebral bodies, a secondpart being equipped for being positioned relative to a second one of thevertebral bodies, and a further part, the further part being capable ofbeing moved relative to the first and second parts; positioning thefirst and second parts relative to the first and second vertebralbodies; moving the further part relative to the first and second partsto distract the first and second parts relative to one another until adistance between the vertebral bodies is at a desired value; and fixingthe further part relative to the first and second parts while thedistance is at the desired value.
 23. The method according to claim 22,comprising the step of anchoring the first and second parts relative tothe respective vertebral body prior to the step of moving the furtherpart relative to the first and second parts.
 24. The method according toclaim 23, comprising the further step of anchoring the first and secondparts relative to the respective vertebral body by a positive-fitconnection.
 25. The method according to claim 24, wherein theintervertebral element comprises a material liquefiable with the aid ofmechanical vibration, and wherein the step of anchoring the first andsecond parts comprises charging the liquefiable material with mechanicalenergy until it becomes liquefied, from an initially solid state, andflows into structures of the bone tissue to form, afterre-solidification, a positive-fit connection with the bone tissue. 26.The method according to claim 22, wherein the intervertebral elementcomprises a material liquefiable with the aid of mechanical vibration,and wherein the step of fixing the further part relative to the firstand second parts comprises charging the liquefiable material withmechanical energy until it becomes liquefied, from an initially solidstate, and flows into structures of at least one of the first part, thesecond part, the further part, to yield, after re-solidification, apositive-fit connection between the further part and the first part orthe second part or the first and second parts.